test-drb December 2007

test-drb@ccmp.vtda.org

215 participants
420 discussions

Emailing: ST506 and-or ST412 hard drives.htm

by lynchaj＠yahoo.com

> From: pete at dunnington.plus.com <http://www.classiccmp.org/mailman/listinfo/cctalk> ---snip--- >> >> There was a signal on some drives that came on the data cable. >> I think it may have been a write protect but I don't recall >> exactly what it was. The ST506 may have used this signal. >> I'm not sure if this is what he is talking about. > > There's a "drive selected" signal, but I think most drives have that. > It's there because the 34-way control cable is daisy-chained but the > 20-way data cable is radial, one per drive. Yes, that may have been it. If he is using just one drive, this shouldn't be an issue. > >> I'd suspect things like step rate and number of heads would >> be more important to him than anything else. > > The other important difference between the ST506 signals and the ST412 > was that the ST506 didn't support buffered seek; the timing of the step > signals had to be slow enough that the stepper motor could keep up. The > ST412 was the first drive that buffered the step signals, so they could > be sent rapidly, and virtually every hard drive after that did too. > This is important because many drives that had the auto step, were really slow using the fixed rate step. I had this problem getting a ST251 to run on my Olivetti M20. The original drive had a fast step rate of something like 6 ms. The ST251 wouldn't work faster than 10ms as I recall but the auto rate was much faster. I think we need to hear from Andrew to see just what it is he is talking about. From his original post, I still think he has something confused. Dwight _________________________________________________________________ The best games are on Xbox 360. Click here for a special offer on an Xbox 360 Console. http://www.xbox.com/en-US/hardware/wheretobuy/ ________________________________ -----REPLY----- Hi, Yes, I'll admit this can be a bit confusing and I am bit puzzled by it as well. I had not heard of anything like it either but I have to believe the VG engineer to know what he is talking about. However, I have heard from a former Vector Graphic engineer who is intimately familiar with the VEDMCS (aka, the integrated FD/HD controller) and he tells me that the ST506's used for the VEDMCS are different than the generic "off the shelf" ST506 hard drives. I believe the stock ST506 is modified or configured to provide the signal in some manner. The different signal is called a "constant index" signal. Apparently, it is similar to an /INDEX signal from a floppy drive interface but the signal tells the HD controller everytime sector 0 passes around. The HD controller requires it for setting up the PLL. Here is an excerpt on the subject from the VG engineer: " All hard drives working with a Vector FD/HD must have constant index. There is a phase locked loop that is controlled by U20 which is CMOS 4040 chip and unless you have constant index the PLL never has time to sync up and gives read errors. " I have seen the VEDMCS driver source code and it specifically lists the ST506 and the ST412 as its only two supported drives. I'd like to start witho one of those and see if I can get it work. Maybe I could convince it to accept a ST225 instead of a ST412 but so far I haven't had any luck. I keep getting "drive not ready" errors. I hope this helps explain this situation. Thanks! Andrew Lynch

18 years

HP Tape drive for Christmas

by silent700＠gmail.com

So on the 24th I trucked up to Milwaukee (from Chicago) for a $100 SGI haul, the star of which was a working Crimson with three hard drives. Brought back the Crimson and some Indigo 2s (which will be for sale/trade/free as soon as I inventory them.) There was supposed to be an O2 as well, but it went missing. So for the pre-arranged price I asked to hunt around the shop for a replacement item, which turned out to be the back-breaking HP 88780B 9-Track Tape Drive! A fair trade-up, I'd say. So I've got it home and onto a table. This may be old-hat to some, but having never used a 9-track before I have to say the air-powered self-threading mechanism is the coolest thing I've seen all month. I loaded a blank tape for the self-test, which passes. Now to get it to write some real data, and eventually use it to rescue some old tapes I've had for years as well as the one I bought at VCF. I'm guessing that any modern *nix machine should recognize it and be able to read it. I planned on using a Sparc IPX or something similarly portable when I get one formatted and loaded. In the meantime, I have my laptop. Is there any chance of getting WinXP to use this beast? I have a SCSI PCMCIA card on the laptop which I've used to read old hard drives, but drivers will be the issue here. I know in most cases the backup software needs to be able to handle the drive as well as the OS - anyone tried to use Backup Exec or any of the other big commercial s/w with one of these? Thanks in advance... -- jht

18 years

updates to the Alpha Micro Phun Machine

by spectre＠floodgap.com

A greatly updated history of Alpha Micro, including their use of alternative operating systems such as UNIMOS/Unix and Pick, and the invasion of the clone systems, is now up on the Alpha Micro Phun Machine. In addition, the models page is tremendously expanded with corrected chronology and more information on loadouts. This is all with the help of Bob Fowler, who graciously allowed me to raid his AMUS document archive and take images. He also put a lot of his software onto a QIC tape for me, but naturally my AM-626 streamer has decided to be recalcitrant, so this will wait for the next update until I can fix it. Also, I recently acquired an AM-1200, and there will be a model page for that as soon as I get it operational. http://ampm.floodgap.com/ -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- The son becomes the father, the father becomes the son, the uncle has a beer.

18 years

ST506 and/or ST412 hard disk drives

by ard＠p850ug1.demon.co.uk

> First, I'm not sure what you mean by ST506 and ST412. I thought > these were different in that one had a signal used for write precompensation > while the other used the same line for a head select. Weren't both of those 4 head drives? THe ST412 is part of a family (ST406, ST412, ST419) which were 2, 4, 6 head drives from what I can see. I thought the ST506 was 4 heads but fewer cylinders. I also thought the main difference between the ST506 and ST412 interface was that the latter alloewed buffered seeks, the former didn't I am still curious as to what the 'speacial' signal is. -tony

18 years

Modem to Modem without a line simulator?

by ard＠p850ug1.demon.co.uk

> The current is used for the carbon mike and to tell the > phone system that the phone is off the hook. Line connected > modems don't have any use for the current and only have > a load resistor there to keep the line connected. Something I forgot about earlier : I think the GPO Modem 13A (A plinth mounted under a normal dial-type phone) could be strapped to draw its power from the line. I don't know the full deatails, I do have one of these modems (300 baud CCITT oriignate only), but I have no diagrams other than the connection lable stuck inside. But there's certainly a transformer-isolated PSU circuit on the board, and one setting of the straps seems to connect the input of this to the line -tony

18 years

Testing

by ard＠p850ug1.demon.co.uk

Just a mail test -tony

18 years

Emailing: Source for EEPROMs.htm

by lynchaj＠yahoo.com

All: I?m in the process of getting a floppy system running on my IMSAI (I should have CP/M running on it tomorrow; a separate book report to follow since I polled this group a few times for info on the topic) and I?ve been burning/erasing a lot of EPROMs to get it done. I have an EPROM emulator somewhere but I can?t find it. Anyway, my programmer can also handle 28C16 EEPROMs. I located some at Jameco ($4@) and at JDR ($4.50@) but I was looking for a cheaper source if possible. Googling produces tons of sites with either data sheets or industrial recovery companies that want to sell 100 of them at a shot. At most I?d probably buy a tube (15 or 20) of them. Any pointers would be appreciated. Thanks again, and Happy New Year to all. Rich -- Rich Cini Collector of Classic Computers Build Master and lead engineer, Altair32 Emulator http://www.altair32.com http://highgate.comm.sfu.ca/~rcini/classiccmp ________________________________ -----REPLY----- Try Unicorn Electronics. I have bought some 28C16's from them before and they are OK. http://unicornelectronics.com http://unicornelectronics.com/IC/EEPROM.html Thanks! Andrew Lynch

18 years

Source for EEPROMs

by rcini＠optonline.net

18 years

Mail formatting

by cclist＠sydex.com

> Date: Mon, 31 Dec 2007 09:41:58 -0600 > From: John Foust <jfoust at threedee.com> > >I beleive the original intention was that 0x7F would be _ignored_. The > >point being you could overpunch any characeter on paper tape to turn it > >into 0x7F (all holes), and thus you could effectively delete that > >character from the tape > > Wasn't it used to indicate that the previous character could > be ignored? No--the use is "Rubout"--erase an erroneous character by overpunching all holes. Deleting characters from punched paper tape is otherwise very difficult without a pair of scissors. Back on topic, one thing that seems to be confused here is the *function* of the newline/carriage return/whatever. One function is as a format effector (i.e. print control; the other is as a record delimiter. Confusing the two roles leads to problems. For example, if CR is used as a record delimiter, then there's no easy way to indicate that the next line on a printing device should overprint the next line on the current one. By the same token, using linefeed as a record delimiter forces the next record to insert spaces in the next record to simulate a vertical motion of the printing position without a corresponding return to the beginning of line. If one is to have character-delimited records, better to use a character whose function is to delimit records rather than control printing behavior. I believe that the Beehive SuperBee sent 1/15 as an end-of-line character rather than CR, at least in screen editing mode. By the same token, 0/8 BS does not imply that a character is to be erased when the printing position is moved back; the implication is that the next character will overprint the previous one. CRT terminals and their simple-minded mode of operation pretty much forced this behavior and it's curious that with our GUI displays that we still mimic the faulty behavior. I recall that this was an issue in the original Videotex spec--IIRC, certain characters could be combined using BS. Cheers, Chuck

18 years

Anyone have a "Chain Train" printer from Data Printer corp? I have ribbons...

by ian_primus＠yahoo.com

Doing some cleaning here at work, and have located several boxes of new, sealed ribbons from old Chain Train printers made by Data Printer Corp. These are some seriously unusual ribbons - about 14" wide rolls. We also have some parts for these machines. Anyone have one of these beasts? -Ian

18 years

← Newer
1
2
3
4
5
6
7
8
...
42
Older →

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb December 2007