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IEEE1394

IEEE1394, also called “FireWire”

“1394 right now is specified to run up to 400Mbits per second and 800Mbits in the future. It will be plug and cable backwards compatible. ”

Often used to transfer movies from digital camcorders machine_vision.html#digital_cameras … machine_vision.html#IEEE-1394_digital_camera

[What is the endianness of CAN ? ]
“CAN we talk? : Distributed systems require protocols for communication between devices. CAN and SPI are two of the most common.” article by Niall Murphy 2003-05-14 http://www.embedded.com/story/OEG20030509S0042

… a text-based protocol. This is how most of the Internet works; HTTP and SMTP are both built on text protocols. This approach allows the protocol to remain architecture agnostic. Text is less efficient than a protocol where each byte is given a meaning, but the upside is a protocol thats easy for a human to read and debug.
…
The biggest difference between CAN and SPI is that the CAN protocol defines packets. In SPI (and serial interfaces in general), only the transmission of a byte is fully defined. Given a mechanism for byte transfer, software can provide a packet layer, but no standard size or type exists for a serial packet. Since packet transfer is standardized for CAN, its usually implemented in hardware. Implementing packets, including checksums and backoff-and-retry mechanisms, in hardware hides a whole family of low-level design issues from the software engineer.
…
There are a number of higher layer protocols that have been layered on top of the basic CAN specifications . These include SAE J1939, DeviceNet, and CANOpen. …
 
points to the Linux CAN-bus driver project http://home.wanadoo.nl/arnaud/
Open DeviceNet Vendor Association, Inc. http://www.odva.org/ (DeviceNet is a more detailed specification for CAN)
information from “Hard real-time connectivity: Its in the CAN” article by Bruce Boyes in _Computer Design_ 1998-01, p. 88
“CAN is a robust network designed for hard real-time distributed control systems in harsh environments. Its an open standard (and the subject of ISO 11898)…” … “CAN is a peer-to-peer network … packets with a maximum payload of 8 bytes … … adept at passing around simple commands or small amounts of data quickly… … not well-suited to moving around large files …” “can go up to 1 Mbit/s, CAN systems most commonly operate at 250 Kbit/s or 125 Kbit/s, because lower baud rates are more resistant to brief bursts of noise.” ” fiber-optic cable also is common. …” “The ISO 11898 document specifies a 120 Ohm nominal impedance using terminated twisted-pair media. … line length versus baud rate … … 40 m, 1 000 Kbits/s … 1 000 m, 50 Kbits/s …”
“low cost and relative simplicity” “Kevin Parkinson … typically uses optically isolated chip-to-bus electronics using RS485 type drivers.”
“Emphasis on content” “When data is transmitted by a CAN node, no other nodes are /addressed/; rather, the /content/ of the message (pressure, voltage, temperature, etc.) is designated by the identifier, which is unique throughout the network. The identifier also prioritizes the message. With care, this prioritizing guarantees the most important messages are transmitted with the least delay. … Arbitration is nondestructive. In the case of an overloaded network, the highest-priority messages still get through. … Latency … is also very low. … CAN hardware also provides message acknowledgment and automatic re-transmission in the event of an error.”
“CAN data bits are either “dominant” or “recessive”. … A frame always begins with a dominant-level SOF (start-of-frame) bit. A dominant bit always “wins” over a recessive bit being transmitted at the same time. … If 2 nodes start transmitting concurrently, each node performs bit-wise arbitration to resolve the conflict. … A transmitter stops sending if it sends a recessive bit, but monitors a dominant bit. That guarantees a lower-priority CAN device immediately stops transmitting, while the higher-priority device continues unimpeded. The lower-priority device waits for the next bus idle time and tries again. … 2 nodes [should] never send the same [arbitration field] followed by different data …”
“… ACK … indicates sucessful message … reception by at least one receiver … the hardware ACK is an important component of CANs real-time capability.”

“For example, a vehicle wheel-speed sensor should transmit its data properly and let other nodes, if any, handle the data as they wish.”
“The RTR bit permits any node to request data from another node.”
“receiving nodes which detect a problem … transmit… in the end of frame space. The sender monitors the error flag, which triggers an automatic retransmission by the sending node.”
“Honeywells Smart Distributed System (SDS) … DeviceNet (initiated by Allen-Bradley) … … DeviceNet and SDS also include specifications for rugged cable and connectors.”
“The CAN in Automation (CiA) group (Erlangen, Germany) promotes the CAL”
“CAN specification 2.0B describes the extended message frame with a 29-bit ID.”
Siemens (SAE81C91), Motorola (MC68376), Intel (i82527), Philips (SJA1000), National Semiconductor (COP87L84BC). offer CAN controllers and/or microprocessors with CAN 2.0B capability.
CAN extended message format (bit field width is not to scale)
| Arbitration field | Control Field | Data field | CRC field | Response field
Arbitration field:
| SOF | 11 bit identifier | SSR | IDE | 18 bit identifier | RTR |
Control field:
| R1 | R0 | DLC |
Data field:
| Data: 0 to 8 bytes |
CRC field:
| 15 bit CRC |

Response field:
| ACK field | EOF 7 bits | INT 3 bits | bus idle (or another node starts transmitting)
SOF: Start of Frame, a single dominant bit
SRR: Substitute Remote Request
IDE: identifier extension bit is recessive for extended format
ID Fields: a total of 29 ID bits for extended frmat
RTR: remote transmit request, dominant for data frames, recessive for remote frames.
R1, R0 are reserved, dominant bits.
DLC: a 4 bit data length code indicates the number of bytes in the data field.
DATA: 0 to 8 bytes. A remote frame contains zero bytes.
CRC: a 15 bit CRC and a recessive CRC delimiter bit. (Covers what ? just the data ?
The entire packet before the CRC ? )
ACK: acknoledgement is a single dominant bit followed by a recessive delimiter bit
EOF: End of Frame: seven recessive bits end a frame
INT: intermission is 3 bits between remote and data frames

For an extended frame, this is a total of 64 to 128 bits (depending on data size). With 8 bytes of data, overhead (non-data bits) is therefore 1/2.





• Jan Axelson http://lvr.com/ has lots of information about RS-232 and RS-485 #rs485

• http://sourceforge.net/projects/libserial/ “A collection of C++ classes which allow the serial port on POSIX systems to be accessed like an iostream object. …”
  
• Programming Notes For Central Data Serial Ports http://www.cd.com/prog.html has lots of useful data on programming PC serial ports (in Unix and WindowsNT). [FIXME: ac968201 says this is offline]
  
• Unix Serial Port Resources http://www.stokely.com/unix.serial.port.resources/serial.card.code.html ???
  
• PC Interfaces and Controlling Devices http://www.epanorama.net/links/pc/interface.html has information about the PC serial port, PC parallel port, IrDA infrared link, USB, IEEE 1394, keyboard, mouse, joystick. [FIXME: copy link to other interfaces I talk about ?]
  

  http://thairobot.com/interface.htm seems to have information about all the same interfaces …
  

  http://www.beyondlogic.org/ seems to have information about all the same interfaces …

  
  
• Computer Interface: Serial and Parallel Port Communications http://engineering.cua.edu/biomedical/faculty/hidler/courses/be497/2001/projects/emg/EMGlinks.html#comp

• Michael Sweet http://www.easysw.com/~mike/ wrote the “Serial Programming Guide for POSIX Operating Systems” http://easysw.com/~mike/serial/
  
• “Use of a PC Printer Port for Control and Data Acquisition” by Peter H. Anderson http://et.nmsu.edu/~etti/fall96/computer/printer/printer.html
  

  Programming The Parallel Port In QBasic http://www.aaroncake.net/electronics/qblpt.htm Programming The Parallel Port In Visual Basic http://www.aaroncake.net/electronics/vblpt.htm
  

  [FIXME: this is about the parallel port, not the serial port ... do I have parallel port information elsewhere ?]

From: helge at siemens.co.at (Helge-Wernhard Suess)
Newsgroups: comp.os.ms-windows.programmer.misc
Subject: Re: Question about serial ports
Date: 12 Sep 1995 11:32:18 GMT
Organization: Siemens AG Austria
Lines: 26

In <3253010398.350698279@ett.se>, <H.Olsen at ett.se> (Hakan Olsen) writes:

>Hello,
>
>I am writing a program that does some commmunication via modem. My problem is
>that I have not found any functions to initialize or communicate with the
>serial ports on a PC. Are there any libraries containing useful functions for
>serial communication? I would prefere if the libraries were for standard C
>as I am not very familiar with C++.
>
>I am using Borland C/C++ 4.0
>
>Any help would be much appreciated!

Look up the OpenComm(), CloseComm(), WriteComm(), ReadComm() etc.
in your SDK helpfile. For a more elaborate communication (X, Y, Z-Modem)
you should get (buy) a communication library supporting some of the
common protocols.

Helge =)

———————————————————-
(c) All Thoughts are Mine — Genuine Genius
———————————————————-
helge at siemens.co.at —– VIENNA — AUSTRIA
———————————————————-
Subject: Re: ADB Physical Specs
From: st93urnu at post.drexel.edu (Aaron D. Marasco)
Date: Fri, 23 Feb 1996 17:24:21 -0500

In article <31233605.5C70@gtri.gatech.edu>, Bryan Dunn
<bryan.dunn at gtri.gatech.edu> wrote:

>Hello all!

>
>Im designing some hardware that will use the ADB interface. Can anyone
>suggest a good reference (on the net or in print) that describes ADB in
>detail?
>
>Thanks in advance!
>
>Bryan

“Guide to the Macintosh Family Hardware: Second Edition”

Tells everything about the Macs up to the IIfx, including ADB, and a
standard is a standard, so it shouldnt have changed (however, this *IS*
Apple were talking about!)

Anyway, it is a book I have for a school class, so I have all the info:

$26.95 US, $34.95 CAN

Addison-Wesley

ISBN 0-201-52405-8

I havent checked any of the online bookstores, you might get it cheaper!
Also, its a paperback, to letcha know.

_Inside AppleTalk, Second Edition_




notes from _Inside AppleTalk, Second Edition_ by Sidhu, Andrews, Oppenheimer[1]. and from AMDs _Analog and Communications Products 1983 Data Book_[2]. and Apple _Macintosh Family Hardware Reference_ (1988) [3]. LocalTalk uses Synchronous Data Link Control (SDLC) frame format and a frequency modulation technique called FM-0. Each bit cell (nominally 4.34 usec -> nominal 230.4 Kbit/sec). differential, balanced voltage signaling over a maximum distance of 300 meters. … transformer provides ground isolation as well as protection from static discharge. “In the preferred hardware implementation of LocalTalk, a Zilog 8530 Serial Communications Controller (SCC) is used.” [1] The classic Macs and the Mac SE [3] both use the 8530 SCC, a 26LS30 differential transmitter, a 26LS32 differential receiver, and a fistfull of RFI filters. The Mac II replaces the 26LS32 with a 75175 differential receiver. (I have no info on other macs) (the Maxim MAX216 Low-Power AppleTalk Interface Transceiver looks interesting). The SCC is clocked at 3.672 MHz hooked to /RTxCa, /RTxCb, and PCLK. on classic, Mac SE, and Mac II. (Mac SE and Mac II has software switching of /RTxCa to the GPiA pin).[3] “dont access the SCC chip more often than once every 2.2 us. … on the Mac SE [and the Mac II] it is not neccessary to do so because [other circuits ensure the proper delay]“[3] “the transmitter and receiver hardware for LocalTalk is built into every Macintosh and AppleIIGS computer, …. and many peripheral devices …” “If you are designing your own AppleTalk hardware from scratch, it is easiest to use a 3.6864 MHz oscillator and a Z8530. This has been tested and works just fine.” [HW 545 - Serial I/O Port Q&As - Technical Notes - Developer Support ] “LocalTalk hardware can detect a flag byte, the distinctive bit sequence 01111110 ($7E).” [1], but i cant find any reference to this capability in [2]. Well, the hardware guys have done it again. Theyre making this gizmo that theyre hooking to the Mac serial port. They say it communicates “like a synchronous modem”. They want it to go at least 500Kbits/sec. “see that Z85C30 on the Mac motherboard there ? the databooks say it can go at 10MHz … cancha just poke the right values into it? dissassemble the Mac ROMs and figure out how Apple did it ? … But of course we want the thing to work plugged into the serial port of *any* Macintosh, including the 1996 models.” I know it can be done; the hardware guys had LapLink for Mac running on 2 Macs (homebuilt cable between them) “See that Oscope ? theyre pumping 750KHz into the HSKi input … LapLink just transferred a megabyte file at rougly 70KB/s.”

65 views

Mac Serial Port

I have pushed the Mac serial ports to 1 Mbps; email me for more info. Comments?

the communications protocol for the Mac QuickCam takes advantage of many of the Mac serial ports to communicate at 918 Kbps (synchronous). /* the protocol description *was* available at http://www.connectix.com/connect/files/driver/mac.pdf */

[1.4] How fast can the Macintosh serial ports really go? ——————————————————–

Orignally the MacOS supported up to an asynchronous data rate of 57600 bps though the serial hardware could support much higher transfer rates externally clocked (as much as 16 times synchronously). The AV and Powermac introduced a different SCC clock and DMA based serial driver which allowed 115,200 and 230,400 bps. …

While the ability to achive these speeds was useful in the days of communications software (see [3.1]) its importance dwindled with the introduction of Intenet communications and PPP (see [5.3]). The reason is that many non-text files on the Internet are already compressed which renders the built in MNP5 and V.42bis compression methods virturally useless. In addition due to limiations in equipment and phone line quality even a 56K modem rarely gets a sustained throughput over 50K.

For these reasons the modem scripts that come with Open Transport have 57600 bps as the maximum serial speed for a modem.

– comp.sys.mac.comm FAQ http://members.aol.com/BruceG6069/csm-comm-FAQ.txt

David Carys experiences

David Carys experiences with a pulse generator hooked to HSKi …. Mac data out (TxD+ and TxD-) changes only on rising edge of clock. (works fine when *input* data changes only on rising edge of clock).

clock specs: 4Vpp seems adequate, but it *must* go below ground. I used a green (all green LEDs are around 2.0 V, its a physical property of quantum electronics) LED in my level-shift circuit to give me +1 V and -4 V on my clock. It was very distorted (more triangular than square), but it worked OK transmitting stuff back and forth between 2 macs. (using custom software).

_Inside Macintosh IV_ has a nice circuit diagram on p. 249.

The Macintosh Toolbox provides support for serial speeds up to a maximum of 57 600 bps. All my standard modem software is set to 57 600 bps; the 2 modems I use can handle talking to the Mac at that speed.

Technically speaking, however, the Mac serial port hardware can go much faster. You just need special hardware and special software.

Ive witnessed a (prototype) gizmo that plugs into the Mac modem port and talks at 1 000 000 bps (roughly 1 Mega-bit / second) with a (1 MHz) pulse generator hooked to HSKi. (Of course, the 2 Macs involved were doing *nothing* but run my communication code).

(The hardware guys cranked it to 2 Mbps — most characters still made it through, but many were lost.). It went that fast plugged into a PowerBook 520 or when plugged into a Quadra 605.

I got the information I needed to write software for a Mac to interface to this gizmo from the book _Inside Macintosh:Devices_ , a few paragraphs that talk about a “synchronous modem” connection.

_Inside Macintosh_ from Apple says that Mac serial port hardware can be made to go at 500Kbps (900 Kbps or more on most recent models) by supplying a appropriate clock on HSKi. the book seems to indicate GPiA is used for devices with *different* transmit and receive rates. Wierd.

the GPi line … it appears that the Mac SE has one connected, while the Mac Classic and the Mac Plus has no connection to that line (?).

I used the “officially sanctioned” call from the new Inside Macintosh books, const Byte external_clock = 0×40;
gOSErr = Control(gOutputRefNum, 16, &(external_clock)); /* set bit 6 to enable external clocking */

This works fine on my PowerBook520c, a Quadra, and a PowerPC (the only machines I tested my homebrew program, cable, and oscillator on). Mac data out (TxD+ and TxD-) changes only on rising edge of clock. Communication works fine when *input* data changes only on rising edge of clock. (This was the easiest to do — I simply connect the same clock to both Macs). (I never got around to testing whether it would still work if input data changes on falling edge of clock — I figure, if it works, dont fix it).

RS-232 is quiescent *low* (normally low, at -5V on Mac serial port) I have succeded in writing a program that uses a toolbox call “set up Serial A to use HSKi as the receive and transmit clock”. The normal serial toolbox calls only let me go up to 57Kbps. They say “its easy — just poke the appropriate values in the Z8530 SCC. If you dont know its address, just dissassemble the Mac ROMs and figure out how Apple did it”. But of course they want the thing to work plugged into the serial port of *any* Macintosh, including the 1996 models. _Inside Macintosh_ from Apple says that Mac serial port hardware can be made to go at 500Kbps (900 Kbps or more on most recent models) by supplying a appropriate clock (on HSKi, I think). I *think* its easier to use the same clock as both transmit and receive, but the book seems to indicate GPiA is used for devices with *different* transmit and receive rates. Wierd. Surely someone, somewhere has done this before; Id appreciate any programming tips, pointers to magazine articles, books, etc. Ill post a summary of emailed responses, as well as a report on how well they work on my Quadra and on my friends Mac PowerPC. -dc

Date: Tue, 5 Dec 89 16:36:44 EST
From: zben at umd5.umd.edu (Ben Cranston)
Subject: Serial port document (long)

MIT EE claims it is benign but confusing. Caveat Solderor…

This document contains notes on the Macintosh serial port and its use, with
concentration on hardware interface issues.

*** DANGER WARNING WILL ROBINSON!!! ***
The DB-25 on the back of a Macintosh is NOT a serial port! It is a SCSI
parallel port. Any attempt to use this connector as a serial port will NOT
function correctly and may cause damage to the Macintosh and/or the equipment
being connected.

The two serial ports of a Macintosh are mini-Din-8 connectors which are
labeled with a telephone (the “modem port”) and a printer (“printer port”).
This is the pinout of the serial connectors. We are looking at the back
of the Macintosh (or alternatively at the BACK of a male plug):

Macintosh Plus Serial Connectors (Mini-DIN-8)

/——###—— 1 HSKo Output Handshake
/ ### (Zilog 8530 DTR pin)
/ 2 HSKi / Clock Input Handshake or extern clk
/ [|] [|] [|] (Depending on 8530 mode)
/ 8 7 6 3 TxD- Transmit data (minus)
| |
| | 4 Ground Signal ground
| === === === |
| 5 4 3 | 5 RxD- Receive data (minus)
| |
| | 6 TxD+ Transmit data (plus)
—-+ === === +—-/
###| 2 1 |###/ 7 N/C (no connection)
##| |##/
| |/ 8 RxD+ Receive data (plus)
——###——/
###

Note this is a RS-422 interface so the signals come in a balanced pair,
a positive (plus) and a negative (minus), for each data signal. As we shall
see below, there is an easy method for matching this to RS-232.

We buy the mini-Din-8 connectors at our local electronics surplus store.
They cost just under four dollars each, but are not quite as nice as the
Apple molded plugs (for example, they dont have the nice orienting-D shape).
We are now carefully removing the pins from the connector, soldering the wires
to the pin, then replacing the pin in the connector body. We fan out the
end of the (stranded) wire into a little umbrella around the head of the pin,
then we solder all around. A “third hand” reduces this task from impossible
to merely tedious.

On the original 128K and the 512K upgrade machines (which have a DB-9 connector
instead of the mini-Din-8) the Output Handshake line was held in a “marking”
condition by hardware (a small resistor to the appropriate power supply rail).
On later Macintoshes there are logic and a line driver for this line. This
change introduces the following incompatabilities:

1. SOME of the older terminal programs dont have the code to explicitly
drive HSKo high.

2. SOME terminal programs drop HSKo when they close down.

3. SOME modems require DTR and will drop carrier if DTR goes away.

If the cable design given below, mapping HSKo to DTR, is used, there are two
recognized pathological conditions which can happen:

A. Cannot use modem at all, because of 1 and 3 together.

B. Modem drops out when switching between terminal programs, 2 and 3 together.

Of course, some people consider B a feature, in that it will hang up the
phone when you switch off the computer. Personally, I hang up the phone when
I am done and I like to switch from terminal program to terminal program.
If one of the above conditions happen, there are only three alternatives.

I. If at ALL possible, set your modem up to IGNORE DTR and stay connected.
Look for a DIP switch for this. I personally made this choice.

II. Use only terminal programs which “properly” drive HSKo.
You get to operationally define “properly”

III. Drive DTR from DSR at the modem end of the cable, as described below.

Macintosh to modem (or other DCE device):

DIN-8 MALE DB-25 MALE

GROUND 4 O–+——————–O 7 GROUND
RECV DATA + 8 O–+

RECV DATA – 5 O———————–O 3 RD (Receive Data)

XMIT DATA – 3 O———————–O 2 TD (Transmit Data)

HANDSHAKE OUT 1 O–+
HANDSHAKE IN 2 O–+——————–O 20 DTR (Data Terminal Ready)

Note that in RS-232 the data signals are inverted (marking is minus) while
the control signals are not (marking is plus). Thus the transmit data
minus signal from the Mac is just right for driving the modem. Leave the
transmit data plus signal disconnected. If you ground this you will short
out a driver, and it will probably get hot. Similarly the receive data
signal from the modem/DCE is inverted, so it can drive the Macs receive
data minus line, but in this case the receive data plus line is grounded to
prevent any extraneous signals from being induced into the circuit.

Note also that we are driving both HSKi and DTR from HSKo so the problems
described above can happen. An alternative arrangement would drive these
signals from the modem/DCEs source of DSR, like this:

+–O 6 DSR (Data Set Ready)
HANDSHAKE IN 2 O——————–+–O 20 DTR (Data Terminal Ready)

Some dumb modems might require Request To Send (RTS) which one would wire
like this:

+–O 6 DSR (Data Set Ready)
HANDSHAKE IN 2 O——————–+–O 20 DTR (Data Terminal Ready)
+–O 4 RTS (Request To Send)

Finally, if you have only 3-wire cable and dont need DTR handshake, you
can wire each side to be happy like this:

HANDSHAKE OUT 1 O–+ +–O 6 DSR (Data Set Ready)
HANDSHAKE IN 2 O–+ +–O 20 DTR (Data Terminal Ready)
+–O 4 RTS (Request To Send)

Macintosh to terminal (or other DTE device):

DIN-8 MALE DB-25 FEMALE

GROUND 4 O–+——————–O 7 GROUND
RECV DATA + 8 O–+

RECV DATA – 5 O———————–O 2 TD (Transmit Data)

XMIT DATA – 3 O———————–O 3 RD (Receive Data)

HANDSHAKE IN 2 O———————–O 20 DTR (Data Terminal Ready)

The same analysis applies with respect to the data signals, except that
in this case the transmit and receive are switched around, since one guys
transmit should be the other guys receive and vice versa. Note receive
data plus is grounded while transmit data plus is left disconnected.

For this particular cable we have wired the terminal/DTEs DTR back into
the Macintoshes HSKi to implement a hardware handshake. Assume the
terminal side is a printer that is being overrun. One of the things these
printers can do is drop DTR. By wiring it through to the handshake input
we make it possible for the Macintosh software to temporarily pause in
sending, until the printers buffers empty out and the printer reasserts
the DTR signal.

Some terminal devices may need to see DSR (Data Set Ready) or CD
(Carrier Detect) or CTS (Clear to Send), in which case they may be driven
>From an appropriate source.

+–O 20 DTR (Data Terminal Ready)
This is probably appropriate +–O 6 DSR (Data Set Ready)
for a communications terminal +–O 8 CD (Carrier Detect)
in which DTR is a totally static
signal and does not move. +–O 4 RTS (Request To Send)
+–O 5 CTS (Clear To Send)

or

+–O 4 RTS (Request To Send)
This is probably appropriate +–O 6 DSR (Data Set Ready)
for a printer that flaps DTR +–O 5 CTS (Clear To Send)
as the buffer fills and empties. +–O 8 CD (Carrier Detect)

The logic is to drive from whichever of DTR or RTS is NOT flapping around
as buffers fill and empty or as the terminal transmits and receives…

To connect directly to an IBM PC we believe CD must be asserted. That is,
an IBM PC will not accept data unless it also sees the CD signal.

128K/512K MACINTOSH

Somebody on comp.sys.mac.hardware asked for cables for a 128K/512K Mac!
I didnt know there were any more of those out there!!! Here are
the corresponding connections, please use these in conjunction with the
analysis and suggestions provided above:

128K/512K Macintosh to modem (or other DCE device):

DB-9 MALE DB-25 MALE

GROUND 3 O–+——————–O 7 GROUND
RECV DATA + 8 O–+

RECV DATA – 9 O———————–O 3 RD (Receive Data)

XMIT DATA – 5 O———————–O 2 TD (Transmit Data)

+ 12 Volts 6 O–+
HANDSHAKE 7 O–+——————–O 20 DTR (Data Terminal Ready)

128K/512K Macintosh to terminal (or other DTE device):

DB-9 MALE DB-25 FEMALE

GROUND 3 O–+——————–O 7 GROUND
RECV DATA + 8 O–+

RECV DATA – 9 O———————–O 2 TD (Transmit Data)

XMIT DATA – 5 O———————–O 3 RD (Receive Data)

HANDSHAKE 7 O———————–O 20 DTR (Data Terminal Ready)

FINAL CLOSURE

On the DB-25 pin 1 is the FRAME ground and pin 7 is the SIGNAL ground.
Equipment that requires connection to pin 1 is badly designed (IMHO).
As a very last resort you might try a 1 to 7 jumper.

As you can imagine from seeing all these alternatives, an RS232 breakout
box is real handy, since you can try all these patches without having to
warm up a soldering iron. The only other thing I can say is:

IF IT DONT WORK, DONT LEAVE IT TURNED ON LONG ENOUGH TO GET HOT!

Communications driver chips are built very ruggedly and will stand an
amazing amount of mistreatment for a short period of time. But if you
let two drivers fight for an hour one or both of them will burn out…

Ive read this over a dozen times to make sure there arent any totally
glaring errors, but I cannot be responsible for anybodys smoked hardware.
Lets be careful out there!

Ben Cranston <zben at Trantor.UMD.EDU>
Network Infrastructures Group
Computer Science Center
University of Maryland at College Park
of Ulm

---

Macintosh Serial Connector (Mini-DIN-8)
(looking into *cable*)

/——###—— 1 HSKo Output Handshake
/ ### (Zilog 8530 DTR pin)
/ 2 HSKi / Clock Input Handshake or extern clk
/ [|] [|] [|] (Depending on 8530 mode)
/ 6 7 8 3 TxD- Transmit data (minus)
| |
| | 4 Ground Signal ground
| === === === |
| 3 4 5 | 5 RxD- Receive data (minus)
| |
| | 6 TxD+ Transmit data (plus)
—-+ === === +—-/
###| 1 2 |###/ 7 N/C (no connection)
##| |##/
| |/ 8 RxD+ Receive data (plus)
——###——/
###

Pin
# Name typical color typical color
(white cable)(grey cable)
1 HSKo red brown
2 HSKi brown red
3 TxD- green orange
4 gnd yellow yellow
5 RxD- orange green
6 TxD+ black (nc)
7 GPi purple (nc)
8 RxD+ blue black

(pin names from _Apple Mac Family Hardware Reference_ 1988)

Laplink accelerator:
using HSKo (typically +4.2 V) and gnd for power, put
-1.5 V to 2.0 V, 0.75 MHz clock on (both) HSKi.
Connected a Quadra 605 to a Mac Powerbook 160; 900KHz clock worked OK but 926 KHz failed.
(1 HSK0)—diode>|–R–+–>+Vcc->oscillator>-||–+—>(2 HSKi)
| |
(4 gnd)-gnd—-diode>|-+ gnd——-LED>|-+

oscillator>-||–+—>(2 HSKi)
|
gnd——-LED>|-+

(another pinout document: ftp://ftp.armory.com/pub/user/rstevew/PINS/mac-232.pin )

---

Date: Wed, 28 Jun 1995 00:15:36 -0500
From: bill at scconsult.com (Bill Stewart-Cole)
Subject: Info-Mac Digest V13 #69

In Info-Mac Digest V13 #69, iedh1 at agt.gmeds.com (Dan Hofferth) writes >Responding to:
>
>>Date: Thu, 22 Jun 1995 17:13:47 +0200
>>From: thomas at mb.ks.se (Thomas H Eberhard)
>>
>>Fast modems with budget mac?
>>
>>LC II (this also apply to the LC and all the Classics including the II and
>>colors) According to “Guru” the modemport only support hardware handshake
>>on output. Does that mean that I cant get fast input speed even with
>>28800 modems??
>
>The Mac Plus, LC, and Classic do _not_ support hardware handshaking. The
>Classic II and LC II _do_ support it, both send and receive. So your “guru”

>is incorrect.

Not quite correct. *EVERY* Mac supports what is called “Hardware Handshaking” in the Mac world. Technically some RS-232 purists will say this is strictly hardware flow control, and NO Mac can implement all the hardware handshaking of RS-232 (which includes hardware ring indication, hardware speed control, and other things) EVERY Mac serial port has a pair of handshake lines, one in and one out. (abbreviated HSKi and HSKo in pinout shorthand) SOME Macs (all but the classic sized models, the //si, and the LC & LC II) also have an additional input on pin 7 (which is disconnected in those other Macs) termed “general purpose by Apple and designated GPi. This is used by some programs like FirstClass (given the rare correct cable) to do hardware carrier detection.

Hardware flow control is done with the pair of handshake lines in all Mac serial ports. HSKo is run to the modems RTS (Request to send) pin, and HSKi is run to the CTS (Clear to send) pin. A good modem cable runs HSKo also to the DTR pin, since that is useful for using DTR in uni-directional flow control and for older (non-compressing and slower) modems. A few cables will also wire GPi to CD, useful in a few programs, but sadly that is still rare in OEM cables. The effect of using an old-style modem cable on a fast or compression-capable modem is in fact that you can only implement flow control on the data stream from the computer, whereas the computer has no way (due to the cable, not the computer) to ever tell the modem to stop. This is a serious problem with slower Macs, which can easily fall behind the data rate of a fast modem.

The reason that many people think the Plus, LC, and other Macs cannot do flow control is that Apples move to the better serial port (with GPi) was somewhat around the same time as the move from vanilla 2400 bps modems to v.42/v.42bis 2400 modems and 9600bps modems. Pure coincidence, but it meant that Apple was making port changes right as people were buying modems that did not work with their old cables. (Some modems even shipped with old-style cables, and in 1990 it was hard to find a hardware handshaking” cable except via mail-order) With Apple using a slightly enhanced serial port on high-end models of the day and high-end modems not working right without a special cable, it is easy to mistakenly connect the two.

Of course I could have just said that I ran a Plus and used “hardware handshaking” for 4 years with 3 different modems that demanded it, but thats not so convincing perhaps. The proof is in the pinouts.

– Bill Stewart-Cole What is Stewart-Cole Consulting? Hell if I know. Ill find out when I finish the web page. Newsgroups: comp.sys.mac.portables From: nirvana at cruzio.com Subject: Re: 150 vs 160 Organization: Cruzio Community Networking System, Santa Cruz, CA Date: Fri, 25 Nov 1994 09:28:11 GMT Sender: nirvana at cruzio.com (Leo Baschy) Lines: 36 rudolf mittelmann <rm at cast.uni-linz.ac.at> wrote: > I tried to use MacRecorder (a serial-device external microphone) on > a PB150 – but it did not work (with the newest MacRecorder driver > installed!). > I also could not get the CP Sound to work with it. > Why? > Did Apple cripple the ROMs to disallow sound input? Or what else > is missing? The problem is that “the” serial port device, the MacRecorder by Macromedia, has code that violates Inside Mac, therefore crashes. “The other” serial port device (a version of Voice Navigator from Articulate Systems) is no longer supported because the company now focuses on high-end automated dictation systems, Ive been told. A possible solution would be to fix the code of MacRecorder, but Ive tried to convince the manufacturers (its been transferred from one company to another) for more than four years without result. The new Connectix serial port camera is neat, but the sound is limited to 5kHz, which is not so good. If anybody knows a serial port sound input solution that works for the PB150 Id be more than glad to know about it and to write about it. We could even help out if anybody wants to fix the MacRecorder code, we have the know-how to rewrite that code from scratch. After all the manufacturer makes money on selling the hardware anyway, so they shouldnt mind if we write software that makes it work. Its just so much work, and little demand. – Leo Baschy nirvana at cruzio.com Nirvana Research (408) 459-9663 —

---

From cary at agora.rdrop.com Wed Feb 1 19:31:33 1995
Date: Wed, 16 Nov 1994 11:30:54 -0700 (MST)
From: Mark Lankton <LANKTON%PISCES at VAXF.Colorado.EDU>
Subject: synchronous serial port
To: d.cary at ieee.org
X-Vms-To: VAXF::IN%”d.cary at ieee.org”
Mime-Version: 1.0
Content-Transfer-Encoding: 7BIT
Status: O
X-Status:

David,

There is a fairly recent Control call you can make to the serial driver
that lets you use HSKi as a clock, at least for receiving. I have never
tried transmitting that way; all I have to do is listen to an instrument.

The call goes like this:
Control(driverNum,16,0×40); /* Set bit 6 to enable external clocking */

By the way, setting bit 7 with this call means DTR will be unchanged when
you close the driver (if you ever happen to care).

I am right in the middle of building some new hardware to use this method;
for years I have used a home-grown get-in-and-fiddle-with-the-Z8530 input
driver. It always worked fine *except* for exploding on PowerBooks, and
if I didnt have to work on PowerBooks and wasnt worried about maintaining
it in the face of the changing device driver API, I would just keep on
that way.

One important note: the external clock signal apparently wants to be 1x
the bit rate, not 16x as you might guess. And I am still trying to decide
how important the clock polarity is.

Information comes from NIM:Devices.

Good luck, and please let me know how it goes for you.

Mark Lankton
Laboratory for Atmospheric and Space Physics
University of Colorado

From cary at agora.rdrop.com Wed Feb 1 19:32:31 1995
Date: 22 Nov 94 05:57 EST
From: intolabb at oasys.dt.navy.mil (Steven Intolubbe)
Subject: high speed serial stuff
To: d.cary at ieee.org

.Hi David,

Do you need to use a synchronous protocol, or do you just need to
externally clock the serial port? The other problem is duty cycle
of the data. Is it a constant stream, bursts, or do you request
what you want when you want it? There is a toolbox call for setting
the external clock mode (on HSKi) but it is in the new inside Mac
books, which I dont have. I accessed the chip directly to set the
external clock mode, and it appeared to work on the 840AV, but the
toolbox would be the best way to do it. As far as synchronous modes
go, I have also done that, all with direct chip register access,
which is was very rude of me. If you want to run a machine in a
synchronous mode, you should write a driver to replace apples serial
manager (I didnt do that because I dont know how). Apple has a
driver for one of their Personal Laserwriters that was supposed to
be close to 1 Mbaud, so if you were in the APDA fold, Im sure they
could help you out.

Hope this helps,
Steve

APDA: (800)282-2732
APDA developers support (408)974-4897

---

Are the 2 serial ports on your machine inadequate ?

Date: Fri, Jun 3, 1994, 20:51:26

The only serial port boards for the Mac I know of are the “Hurdler” and the “Hustler” from Creative Solutions Inc.
404-441-1617
4701 Randolph Dr. Suite 12
Rockville, Maryland 20852

There are *lots* of serial port boards for the PC.

17 views

protocol_considerations

If you design a new serial protocol, here are some ideas and suggestions you may want to consider:

• Say your receiver is busy for a few microseconds and drops a character or two. You might be able to check for a FIFO buffer overrun hardware flag.
  
• When you turn on a device, how does it know when to start talking ? Who talks first ?
  
• The bit-synchronization problem:
  

  When a receiver is first turned on, how does it know where one transmitted bit ends and the next starts ? Also, what is the bit rate ? Pretty simple for clean RS-485 (and most other hard-wired communications hardware) where you can just watch the edges; more difficult when there is noise (as in nearly all wireless hardware).
  

  Often dedicated hardware synchronizes things to the nearest byte; then higher-level protocols in software deal with frame synchronization.

  
  
• The frame-synchronization problem:
  

  Say the device that is *supposed* to talk first starts talking, but the other device doesnt get turned on until the middle of a “sentence”. How does the receiver know to throw away the (incomprehensible) rest of the “sentence”, and re-synchronize at the start of a new sentence ? (Same thing applies to buffer overrun).
  

  Typically one re-synchronizes by transmitting a unique byte sequence (a “header” or “start-of-message”) that will not (or “probably will not”) be embedded in the middle of a sentence.

  Including the newline and/or carriage return ( suggested by Dmitri Katchalov Date: 27 Jan 2000 ) in this byte sequence helps make it more human-readable.

  
  
• Robert Morris http://www.pdos.lcs.mit.edu/~rtm/ claims that “the Grid routing protocol lets collections of radio-equipped nodes automatically configure their own cooperative network, without relying on any pre-installed infrastructure. He also suspects “a power-saving scheme for an ad-hoc net, that allows radio receivers to spend most of their time turned off. … [perhaps] elect one node per region to buffer messages, so that other nodes can wake up from time to time and poll. Batch traffic, use geo routing to improve batching effectiveness by favoring batching over shortest path. Overall point: we will actually save you battery power, so dont worry about battery used by forwarding for others. [FIXME: link to low-power electronics]
  
• http://members.tripod.com/~mdileo/ “The Tiny Embedded Network is an Open Protocol I designed to interconnect embedded devices in a local area network. The protocol specifications are free and open and I plan to make available the basic routines as well. Is this a power + data bus ? Lots of other PIC stuff. [FIXME: PIC]
  
• CO149s Fundamental Dicta(TM) http://muppetlabs.com/~chris/dicta.html lists lots of protocol design tips, including:
  
  
  
  • 1. The packet has to know how to get back, too.
    
  • 3. The network you are using is experimental technology and always will be.
    
  • 5. The network is constructed of physical components.
  
  
• Subject: Embedded RS-485 Protocol Needed! Newsgroups: comp.arch.embedded

• [FIXME: summarize]
  

  On Newsgroups: comp.arch.embedded , sometime before 1999-01-29, Edward K asked: >I need a small (low C code size), simple protocol to drive a proprietary
  >network based on RS-485. I dont want to get into TCP/IP for obvious reasons.
  >The clients on the RS485 bus would be based on a small 8 bit micro so speed
  >and efficiency are important.

  In response, Robert Reimiller 1999-01-29 suggested:
  

  
  

  I have a small network (about a dozen nodes right now) using PIC processors. Although it doesnt use RS-485 voltage levels, the operation is about the same. It uses a very simple message packet : Length – 1 byte
  Source ID – 1 byte
  Destination ID – 1 byte
  Message Type – 1 byte
  <variable length message>
  Additive Checksum – 1 byte
  Exclusive-OR Checksum – 1 byte

  This is a binary protocol so I used SLIP framing characters to determine the packet boundaries, very simple to implement.
  

  A practical next step would be to use UDP/IP Packets, that way you could interface the system to router that supports SLIP.
  

  Bob

  
  

  In response, Ian Wilson 1999-01-29 commented:

  Length as the first byte can cause all sort of mess in a noisy environment – consider what would happen to the when it receives noise. It would read the noise as a length and go off happily looking for the next x bytes before trying to crack the packet and seeing a back checksum. If the channel is very noisy so that you are getting continuous transitions at you receiver you can completely lock out you network. A better header for a noisy channel is a header sequence that is fixed. I does add overhead but will minimise the amount of false packets.
  

  We use a time passed poll response system quite often. The master polls a slave and the waits for a response – if the reply has not started in a few milli-seconds the master assumes no reply is going to happen. Since replies are longer than a few ms this increases throughput on networks with lots of devices (128 or 250) where the most common reply is “nothing to report”.
  

  Also consider adding a sequence number to the packet. If a slave sees the same sequence number it saw on the last poll it knows the master did not receive its last reply – saves having a seperate ACK reply from the master to the slave. the master holds a differenet seq number for each slave and only increments it on a successfully decoded reply. Keep seq number = 0 as a special case that forces the slave to reset its seq number. Let the seq number increment wrap around from 255 to 1.
  

  Ian Wilson ——————————– Considered Solutions considered@ozemail.no.spam.com.au (do the no spam thing to make a valid email address)

  
  

  Mark Odell 1999-01-29 commented:
  

  
  

  Xmodem sends the length byte followed by the ~length byte. Then a checksum at the end. It was unlikely that the length and ~length would screw up randomly to still work. Besides, a practical max. packet size can help prevent you from going too far off in the weeds.
  

  My RS-485 protocol ran on 8051s with a single master that polled all 20 slave devices for status. I think the packet was destAddr, len, ~len, payload[len], 8-bit checksum. Worked okay for me over about a mile of total network distance.
  

  - Mark

  Subject: Re: Embedded RS-485 Protocol Needed!
  Date: 31 Jan 1999 00:00:00 GMT
  From: Ian Wilson
  Newsgroups: comp.arch.embedded

  <notjimbob at worldnet.att.net> (James Meyer) wrote:

  >On Fri, 29 Jan 1999 04:15:07 GMT, leafs at ozemail.com.au (Ian Wilson)
  >wrote:

  >>back checksum. If the channel is very noisy so that you are getting
  >>continuous transitions at you receiver you can completely lock out you
  >>network.

  > One would think that if the channel were getting continuous
  >transitions because of noise, that the channel would be completely
  >useless and *no* combination of packet parameters would be any better
  >than any other.

  No – this is not the case. Many RF receivers do not squelch (turn
  off) their outputs when the is no transmission – as the carrier detect
  circuit is often more complex and less reliable and more power hungry
  than the receiver (in micopower applications). So you have continuous
  streams of noise induced transitions. When a transmission arrives it
  is much higher than the noise level and so the receiver behaves
  correctly. What you dont want is the noise induced stuff to bugger
  up your network throughput.

  This sort of thing can happen even on wired networks – where you have
  heavy machines turning on and off or thyristor circuits nearby. Maybe
  not to the same degree but you can get false transitions. If a packet
  is not designed well then the network can fail. This is where:

  1) fixed header sequences,
  2) timeouts,
  3) error detection/correction codes,
  4) Ack/nack protocols

  make the difference between a system that works in good conditions
  only vs one that is truely robust. In designing for volume making a
  system robust at the expense of a few weeks of software and protocol
  design is definitely the way to go.

  Ian Wilson
  ——————————–
  Considered Solutions
  considered@ozemail.no.spam.com.au

  (do the no spam thing to make a valid email address)

  
  

  
  

  Subject: Re: Embedded RS-485 Protocol Needed!
  Date: 01 Feb 1999 00:00:00 GMT
  From: Bill Gatliff <gatliff at haulpak.com>
  Organization: Komatsu Mining Systems
  Newsgroups: comp.arch.embedded

  …
  

  SAE has a standard called J1708. Basically, all it says is that an idle period of ten or more bit times between bytes marks the end/begin of a packet, packets are at most N bytes in length, and that each packet starts with a destination byte and ends with a checksum. For the most part, you can put whatever you want inside.

  In a noisy environment or one where collisions can occur (like RS485), you *do not* want to depend on receiving a length byte. Idle timing is the best way to go.
  

  Likewise, you dont want to deal with a negative acknowledgement (where the receiver tells the sender that the packet was corrupted). Instead, only acknowledge the correctly received ones, and let the transmitter resend a packet if it doesnt get a response.
  

  To do it right all you need is about 50 lines of C code– I think even the timer is optional if youre clever.
  

  Heavy-duty trucks arent the worst network environment in the world, but theyre pretty bad. Despite this, J1708 works very well– nearly every truck on the road today uses it.
  

  Just my $0.02.
  

  b.g.
  

  – William A. Gatliff Senior Design Engineer Komatsu Mining Systems

  
  
• “An additional timeout on the receiver end to stop it from hanging within a packet”
  
• S.N.A.P. Scaleable Node Address Protocol http://www.hth.com/snap/ “a free and open network protocol.” has free source code for AVR, PIC, Palm Pilot, and other popular processors.

60 views

standard protocols

• http://webopedia.internet.com/Standards/Communications_Standards/ (pointers to the Hayes AT command set for modems, the RS-232c standard, the RS-485 standard, the CCITT Group 4 fax standard, and several file transfer protocols). [FIXME: last time I checked, left out any mention of S11 -- perhaps give them the pointers below ?]

http://www.rad.wfubmc.edu/~chim/modemstuff/chapter06.html#6.4 has lots of details on the “S” registers, including the S11 DTMF Dialing Speed register. For example, S11= sets the DTMF pulse time to milliseconds and the time between pulses to milliseconds.

http://www.gem.co.za/FAQ/FRAMES/Hayescommands.html also documents S11.

http://www.citilink.com/~kae/faq/connecting/general/hayes.html claims that the minimum value for S11 is 50 ms, which seems incorrect — my modem works fine with S11=[FIXME]

Protocols/Standards/Guides http://www.repairfaq.org/filipg/LINK/F_LINK_IN.html#LINKIN_004

Controller Area Network (CAN) #can

Standard for Sensor Transducer Interface http://standards.ieee.org/announcements/electindustrange.html

IEEE P1451.0 (TM), “Standard for a Smart Transducer Interface for Sensors and Actuators; Common Functions, Communication Protocols, and Transducer Electronic Data Sheet (TEDS) Formats,” will be a new standard containing a common set of functions, communications protocols and TEDS formats for various physical communications media. It will aid interoperability among IEEE 1451 (TM) standards and simplify the creation of standards for different physical layers. 

Before you begin, youll need to back up any files you want to keep. Unfortunately, you cant use any of Vistas built-in backup software for this, because XP doesnt include any tools that can read Vista backups—understandable but a shame. Your best bet is to copy your data onto an external hard disk manually (via a USB or eSATA connection) so that you can easily get it back once XP is up and running. Make sure you back up the entire C:Users folder, which will catch your Documents directory, anything on your desktop, and application data such as stored e-mail.

Recovery procedures vary widely, so consult your PCs manual for details. Typically, the recovery software wipes the hard drive clean and then places a preinstalled copy of Windows onto the drive, complete with all the drivers and demo software that you got with your PC when it was new. When its done, hook up your backup drive and copy your files back into position

8 views

From\ luxuo.com

23 views

Kaspersky® Virus Removal Tool is an utility designed to remove all types of infections from your computer. Kaspersky® Virus Removal Tool implies effective algorithms of detection used by Kaspersky Anti-Virus and AVZ Antiviral Toolkit. 

Highlights:
Easy interface.
Can be installed to an infected machine (Safe Mode supported).
Integral search and removal of malicious software: effective combination of signature detection and heuristic analyzer.
System Analysis and interactive scripting language.
Freeware. 

System requirements
Microsoft Windows 2000 Professional (Service Pack 4 or higher)
Microsoft Windows XP Home Edition (Service Pack 2 or higher)
Microsoft Windows XP Professional (Service Pack 2 or higher)
Microsoft Windows Vista Home Basic (32-бит)
Microsoft Windows Vista Home Premium (32-бит)
Microsoft Windows Vista Business (32-бит)
Microsoft Windows Vista Enterprise (32-бит)
Microsoft Windows Vista Ultimate (32-бит) 

Download : Kaspersky Virus Removal Tool v7.0.0.290(2009.01.05) 

HomePage : http://www.kaspersky.com/removaltools

874 views

The all new Apple MacBook Air will set you back $1799 for the standard model which is not bad considering you are getting a breakthrough in design and technology, and yes you are getting the latest in technology on the laptop front.

The MacBook Air is stirring quite a craze at the moment with talks left, right and center on how good it is and much more, the most impressive we would say has to be that the full sized laptop is only 0.16 to 0.76 inch of sleek, sexy and sturdy anodized aluminum and with a weight of only 3.0 pounds.

The Apple MacBook Air has a 13.3-inch widescreen LED backlit MacBook Air display of which the 1280-by-800 resolution gives you a perfect and yet vibrant image with rich colours and full brightness as soon as you open the lid, not only that you will also get full screen performance within the slim design.

The keyboard is similar to that of the normal MacBook but with the added benefit of backlit key illumination, there is a built in ambient light sensor which will automatically adjust the keyboard and display brightness for optimal visibility, and the oversized multi-touch track-pad makes it a little bit better as well to use.

For more information and option to buy please visit here.

19 views

A new laptop

• If you are feeling really generous this holiday season, you can get that special someone a new laptop. After all, laptops are one of the most wanted items on peoples Christmas lists this year. All of the major players have been working to make their laptop offerings more attractive heading into the 2007 Christmas shopping season.
  
• Dells lineup of Inspiron 1520 computers (top left) comes in eight different colours and pack a 15.4-inch screen, 1 gigabyte of RAM, a 120 gigabyte hard drive and an Intel processor running at 1.46 Ghz. The systems come with Windows Vista Operating System and can be customized. Pricing on the 1520 starts at $749.
  
• HP continues to be a market leader in PC sales. Looking at the companys Pavilion DV9600 (by itself above) entertainment series laptop makes it easy to see why. The computer comes with a high definition 15.4-inch screen, an AMD processor running at 1.9 Ghz, one gigabyte of RAM and a 160 gigabyte hard drive. It also comes with TV outputs and a remote, so you can hook the laptop up to a television and play all of its multimedia content. The system can be customized. Retail pricing starts at $949.99.
  
• For the Apple Inc. enthusiast, the companys latest MacBook Pro surely wont disappoint. Based on the Intel Core Duo processor, these little laptops pack a wallop. The computers come with a 2.2 Ghz processor, 3D graphics cards, two gigabytes of RAM and a 120 gigabyte hard drive. The systems can be upgraded. Pricing starts at $2,199

8 views

Western Digital was created in 1970 in California. This company specialises in data storage solutions and manufactures internal and external hard drives for home users and businesses.

Through its Ontrack® Data Recovery services, Kroll Ontrack offers Hitachi hard drive recovery solutions and multiple service options:

• Any interface: (IDE, EIDE), Serial ATA (SATA), SCSI, SAS, and Fibre Channel
  
• Any combination of drives: single hard drive or multiple RAID drives
  
• 2.5″ Hard drives
  
• 3.5″ hard drives
  
• Laptop hard drives 2.5″ SATA 150MBps, SATA 300MBps
  
• Desktop hard drives 3.5″ SATA 150MBps, SATA 300MBps
  
• EIDE drives
  
• External/USB drives

44 views

 

25 views

Previously, Service Pack 2 for Windows Vista and Windows Server 2008 was only available to select partners — “Technology Adoption Program” customers.  Today it is free to download to any MSDN or TechNet subscribers, and it goes live for the general public tomorrow through the Customer Preview Program (CPP).

Microsoft describes:

The CPP is intended for technology enthusiasts, developers, and IT Pros who would like to test Service Pack 2 in their environments and with their applications prior to final release. For most customers, our best advice would be to wait until the final release prior to installing this service pack.

For those of you who choose to test this service pack, we encourage you to install the beta as soon as you can; your feedback will help us to ship a solid and stable service pack for Windows Vista.

As with previous service packs, SP2 bundles Windows Updates released since SP1 into a single source.  It also adds support for key new standards.  One update is Windows Search 4.0 which should provide faster searches and improved relevancy in results.  The update will also ensure that Vista and Server 2008 are compatible with the latest Bluetooth tech, via the Bluetooth 2.1 Feature Pack.  Native recording to Blu-Ray on Vista is also now supported at last.

A new utility called Windows Connect Now (WCN) is also added to help users set up wireless networks more easily.  In order to synchronize files across time zones, Microsoft also adds exFAT file system to support UTC timestamps.

Many other minor features are also featured in the new service pack.  Overall Microsoft hopes that it makes Windows Vista and Server 2008 use a bit easier and more intuitive, while fixing outstanding issues.

Head on over to TechNet tomorrow if you want to download SP2 as part of the Customer Preview Program.

71 views

Unless ATI has something serious to pull out of its sleeve at CES 2009, the crown will go back to NVIDIA it seems. Its been rumored for a while now that NVIDIA will launch a new video card with dual GTX 200 GPUs at CES 2009 in a few weeks. Today those rumors become fact when NVIDIA allowed a few publications to publish an early preview of the GTX 295.

We now know that the GTX 295 will use dual 55nm GTX 200 GPUs and according to Guru 3D, the specs of the beastie are odd. The 295 has the same memory and core frequencies of a pair of GTX 260 GPUs, but the GPUs enjoy the same shader power of a pair of GTX 280 GPUs.

Total memory for the card is 1792MB, each GPU has 240 shaders, core frequency is 576MHz and shader frequency is 1242MHz. With that, much performance on tap power consumption might be a concern. Guru3D couldn’t provide any specific numbers on power consumption, but did say that it can peak at around 289 watts under load. Power consumption is said to be under the ATI X2 cards.

Visually, the card looks like any other NVIDIA reference design with black and silver coloring. In addition to the pair of DVI ports on the card, the reference design also offers a HDMI out. I would assume the addition of the HDMI out or DisplayPort for that matter will be up to the card partner. We will probably see many of the cards with DVI out only.

Performance is really what gamers want to know when a new video card is released. Guru3D ran the card at 2560 x 1600 on Far Cry 2 and the game was set at HQ DX10 mode, 4xAA and 16x AF for testing. The review found that the GTX 295 provided 54 FPS compared to the ATI Radeon HD 4870 X2s 49 fps at the same settings. However, when the AA was jumped up to 8x, the performance lead was in the Radeon 4870 X2s favor with 31 FPS compared to 24 FPS for the GTX 295.

But what about Crysis you ask? NVIDIA won’t like to hear that at 2560 x 1600, DX10, 2x MSAA and Gamer quality mode the GTX 295 turned in 19 FPS compared to the 4870 X2s 25 FPS. However, when you bump the resolution back to 1920 x 1200 at the same settings the performance gain is again markedly in the GTX 295s favor at 49 FPS compared to 36 FPS for the 4870 X2. Dead Space was the clear winner for the GTX 295 where at 2560 x 1600 it turned in 149 FPS compared to the 4870 X2s 80 FPS at the same settings.

The GTX 295 is set to launch on January 8 at a price of roughly $499. Save your Christmas money boys and girls.

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• Intel 945GM chipset with ICH7-M DH
  
• Dual-channel DDR2 667MHz support
  
• Intel Gigabit LAN
  
• Integrated Intel GMA 950 graphics
  
• Realtek ALC 882M audio codec
  
• 2x SATA with RAID 0, 1
  
• 2x SATA2 with RAID 0, 1
  
• 1x external SATA

The N4L-VM DH is certified for Intels Viiv technology, but surprisingly, doesnt seem to be able to deliver quite enough to be a true media PC. With the integrated GMA 950 graphics, the board is unable to decode high definition H.264 in hardware, which should be on the list of any new PC with a focus on home theater experiences. However, those who are concerned with audio will be happy to know that the N4L-VM DH supports Dolby Digital Live, which allows the motherboard to output a Dolby Digital 5.1 signal. This has been a highly requested feature ever since NVIDIA first launched its SoundStorm enabled nForce chipset several years ago. The board uses a Realtek ALC 882M codec for audio duties, which is able to output an impressive 192kHz/24-bit signal on all 8 channels (analog).

ASUS says:

Even with the compact size, the Intel Viiv-ready and Windows MCE-compatible N4L-VM DH comes with robust multimedia features. The TV Out connector embedded on the motherboard provides a gateway to view memorable digital media on big screen such as LCD TV, while the ALC 882M 8-CH high definition audio with S/PDIF Out completes the experience for overall audible pleasure with Dolby Master Studio. Additionally, with the purchase of ASUS R-DVI-ADD2 card, DVI output is made available for the finest viewing solution.

Supporting both Core Solo and Core Duo processors, as well as the latest memory technology, audio technology, the N4L-VM DH may be the right product for those looking to start a good home theater PC. For those who are looking for more serious video performance, one of the recent PCI Express products from ATI or NVIDIA will have to be used. Those who are content with the onboard graphics can purchase ASUS R-DVI-ADD2 board, which will provide DVI output for full digital output

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 Stop the Green Ribbon of Death
Any Vista user is likely to recognize with fear the green progress bar that sometimes appears across the top of Windows Explorer: If its there for more than a few seconds, that could mean Explorer has crashed. Regardless, youre stuck waiting as long as a minute for a simple Explorer window to become usable! To reset Explorer without restarting Windows, press Ctrl-Shift-Esc, choose the Processes tab, and click the Image Name column header to sort the list. Select each instance of Explorer.exe in the list and click End Process to close it. Dont panic if you lose your desktop along the way; from Task Managers File menu, select New Task, type explorer, and click OK to restore your desktop. 

Unfortunately, there are many reasons Explorer may hang or crash. One fixable culprit is Vistas thumbnail display. If you open a folder with a corrupt or empty video file, a garbled photo, or any media file that uses a defective driver (called a codec), Explorer crashes while generating the thumbnail. To fix the problem, rename the extensions of troublesome files (for example, myvideo.wmv to myvideo.wmv.broken). 
You can also stop the crashing by disabling thumbnails altogether. Open Folder Options in Control Panel, choose the View tab, select Always show icons, never thumbnails, and click OK.  

 

Broken media files often cause Windows Explorer to crash while it tries to make thumbnail previews for them. 

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In the beginning of 2007 we witnessed the release of Windows Vista to a thundering snore, followed shortly thereafter by growing frustration at the softwares poor performance, lousy hardware support, and remarkable ability to crash with no input from the user at all. So Microsoft snapped into action, and more than a year later we got Service Pack 1, which fixed, well, a bit. 

Surprisingly, most of Vistas annoyances are fixable. If youre willing to roll up your sleeves and do some tweaking, you can turn Vista into a pretty great OS. First up: Windows Explorer. 
Cure Vista Explorers Amnesia 

Windows Explorer has a nifty thumbnail display that shows iconic previews of your pictures, videos, PDFs, and even MP3 album folders. But accompanying this eye candy is Explorers baffling inability to determine the type of files in a given folder, which leads to the wrong view almost every time. This is why you may see spreadsheet files as thumbnails and JPEG images in the Details view, and why changing the view doesnt ever seem to stick. 
The root of the problem is templates, Vistas cumbersome method of saving different view settings for different types of files. You can right-click a folder, select Properties, and then click the Customize tab to choose the template to use for that folder (Pictures, Documents, and so on), but that alone wont stop Explorer from ignoring your preference and picking whichever template it wants. 
To fix the problem, go to www.annoyances.org/exec/show/choosetemplate and download ResetExplorer.exe and ChooseTemplate.reg. Double-click ResetExplorer.exe and answer Yes to clear Explorers cached data. Then double-click ChooseTemplate.reg and answer Yes to apply the patch. From Windows Explorers Organize drop-down, select Folder and Search Options, and then click the View tab. From the Default Folder Template branch in Advanced settings, choose how youd like all folders to be viewed by default and click OK.  

Thereafter, Windows Explorer will stop guessing at a folders contents and will use your preference each time. To forcibly switch the template for a folder or branch, use the Customize tab as described above. To save new view or sorting preferences for the currently selected template, go ahead and make those changes, and then return to the View tab (also described above) and click the Apply to Folders button. 

 

After applying the Default Folder Template Patch, these new options will appear in your Folder Options window, enabling you to override Windows Explorers propensity to automatically pick the wrong view settings for your folders. 

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GTX 200 Architecture Features

The chip powering these two new graphics cards, called the GTX 200 chip, is an absolute monster of a processor. Nvidia proudly proclaims that its the biggest processor TSMC (Nvidias primary chip fabrication partner) has ever built. Its not just a clocked-up or expanded version of the G92 chip powering Nvidias most recent high-end cards, but a totally new architecture.

The basic layout of the GTX 280 looks like this: You have a geometry shader processing unit, vertex shader, and setup/raster units. These feed into the unified shader array of no less than 240 stream processing units. Thats 10 blocks of 24 shader units, each block is three groups of eight.

Some L2 texture cache sits between these and the memory interface units, typically referred to as “ROPs” or render back-ends (eight “blocks” of those with four-per-block, which is double the ROP power of the G92).

click on image for full view

Each stream processor includes a register file twice the size of those in the stream processors of earlier Nvidia chips, along with a floating point compute unit, an integer compute unit, and a move/compare unit. Theres also a double-precision floating point unit (IEEE compliant), which is useful for some GP-GPU tasks but not particularly handy for graphics.

Call that configuration one processing “core,” if you will. Eight of them each access a 16K block of local shared memory. Three of those eight-processor groups together access the same bank of L1 cache, creating a 24-unit processing “block.” The block has eight texture address/filter units associated with it. The GTX 280 chip has 10 of these blocks, for a total of 240 stream processors and 80 texture units.

A block diagram of the GTX 200 GPU’s stream processing unit, 24 compute cores. (source: Nvidia)

In the GeForce GTX 280 products, all of these functional elements are enabled. In the GeForce GTX 260 products, some of the units are disabled. These are typically called “salvage chips,” where GPUs that had some defects can have certain parts disabled and still function well as lower-performing parts, allowing Nvidia to effectively use some of the “bad” chips on a wafer.

In this case, the GeForce GTX 260 cards have two blocks of stream processors disabled for a total of 192 stream processors and 64 texture mapping/filtering units. One of the memory access/ROP units is also disabled, for 24 render back-ends instead of 32.

Whether or not you consider the GTX 200 GPU an extension of the G92 class or not is a matter of perspective. Certainly some of the capabilities are similar, and there are no added support for features present in DirectX 10.1, for instance. On the other hand, there are some significant tweaks to the design.

The scheduler has been upgraded to handle more threads at once, which it would need to do to effectively utilize all those stream processing units. We already mentioned the larger register file and support for double precision floating point math. Instruction co-issuing in the stream processors is now more efficient. Texture filter units employ a more efficient scheduler, which Nvidia claims is 22% more efficient than those in the G92 chip.

The blend rate of the ROP units is doubled (per-ROP) compared to previous generation chips. Geometry shading performance, a real sore spot of the G80 and G92 generation GPUs, has been massively improved in the GTX 200 GPU

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