Al,
I have the original Motorola paper version of AN1123. I?m happily to scan
it for you.
I have a pretty complete set from an139 into the 1100s if there are others
you need.
Regards,
Stan Ruppert
So in the continuing quest of fixing my second RL02 I replaced the heads
and found the drive was slow and would generate about 80 block errors on
a pack where my reference RL02 drive would never generate more than 10.
After doing a positional radial check (fine) and a head alignment check
(head 0 and 1 were way off from each other and head 0 was on a crest of
the stepper motor (the part where you are between steps, highly
unstable). Adjusting that so head 0 and 1 were in a valley on the
stepper motor (inherently stable) the drive was much quicker but still
would generate about 80 errors. Odd.
So on a lark I swapped the head amplifier module from the good drive to
the suspect drive. Bingo, 10 errors. So the issue is in the head
amplifier, maybe the voltage was too low.
Next step was to check the read signal amplitude: Because I have a
reference drive I decided to check the signal voltage at track 0 on the
reference drive, then move the same pack to the problem drive and
verify. On the reference drive track 0 has a signal value of a smidge
below 1.5 volts on head 1. On my suspect drive the signal value was 1v.
Adjusted it up to 1.5 volts and errors went down to 9. Not bad. Went up
to 1.6 volts and errors went down to 6.
Hm.
So a question: Is it a problem to adjust the read amplitude up, and if
so how far can you go. The manual says 2.25, is there a benefit of
running up that high? More important, does adjusting the read amplitude
also change the write current through the heads? That could result in a
pack that may be readable, but will be a mess when written to.
What would be nice would be to have a blue amplitude reference pack, but
I don't have one of those. Also I haven't tried any other packs in the
suspect drive, but maybe I should adjust the amplitude in my reference
drive as well.
Thoughts?
C
(All readings done with a tektronix scope. I haven't checked the
calibration in awhile, but it should be reasonably in sync)
All,
Another thing that surfaced recently on my pile is a manila envelope containing a big photocopied stack of papers, with a title page saying:
?
Interfacing the Commodore PET
by Bill Durham, David Paul, and jim Wilman
University of Arkansas.
?
It?s got about 45 pages of text, interspersed with block diagrams showing chip in/out signals and snippets of BASIC code, then a repeat of all that, then a copy of the 6502 instruction set and copies of multiple data sheets for various integrated circuits.
Thought I identified an interested party on the list, but no response to PM, so offering it to all. Free to a Good Home, usual terms, first response unless I hear from Al K. before I ship in which case he gets it instead.
- Mark
210-522-6025 office
210-379-4635 cell
All,
next thing in my disposal pile.
3-ring binder, containing a repro copy of the subject line and a 5.25? floppy labelled ?Apple II DOS 3.3 System Master For Apple II, II+, and IIe?.
computer is given away a while back, should have sent this with it. I bought it in 2006 and won?t use it. I think all reproductions, not originals. FTGH.
- Mark
210-522-6025 office
210-379-4635 cell
I'm having some trouble getting Frotz 2.50 ported to TOPS20. Version 2.32
with dumb interface compiles fine under KCC. With 2.50, there are several
preprocessor lines that include parentheses. For instance:
#if UINT_MAX == (1UL<<32)-1UL
typedef unsigned int uint32;
#else
typedef unsigned long uint32;
#endif
What's a better way of accomplishing this?
--
David Griffith
dave at 661.org
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
With his express permission, I'm forwarding a mail from a public list.
I am interested in Gene's comments about the design of SCSI, but I
don't know enough electronics to judge.
I thought others here might.
I have trimmed the mail a little to the relevant parts.
--
Liam Proven - Profile: https://about.me/liamproven
Email: lproven at cix.co.uk - Google Mail/Hangouts/Plus: lproven at gmail.com
Twitter/Facebook/Flickr: lproven - Skype/LinkedIn: liamproven
UK: +44 7939-087884 - ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053
---------- Forwarded message ---------
From: Gene Heskett <gheskett at shentel.net>
Date: Wed, 8 Jan 2020 at 17:29
Subject: Re: External Disk Intrusion
To: <ubuntu-users at lists.ubuntu.com>
On Wednesday 08 January 2020 09:01:35 Liam Proven wrote:
[...]
> The thing is that actual SCSI cabling faults are very hard to
> diagnose. We used to have internet jokes about them and the need for
> sacrificial goats or chickens, but of particular colours for different
> cable types, pentagram drawn in blood, holy candles, etc.
>
And all that pickityness can be laid at the feet of a bean counter
between the interface card designer, who specified a $2.00 schotkey
diode for buss isolation, which had a maximum voltage drop across it of
perhaps .1 volts, and changed to have an 8 cent Si diode with .666 volts
drop across it, thereby lowering the logic one voltage by .45 volts.
Since the logic one at the logic chips inputs had to be at lease 2.2
volts, and the nearest set of termination resistors gave 3.0 volts when
this buss isolation diode was replaced with a short, but with the cheap
Si diode in there gave a logic one voltage closer to 2.4 most of the
circuits noise margin was used up and considering that same bean counter
crossed out the 5% terminators in favor of 20% tolerance, the result was
predictable.
The situation was much better when active terminations came into use, but
by that time the scsi buss's reputation was doomed.
But back in the day of the bottom 190 market tv stations were generating
their on air gfx needs with a bank of Amiga computers, every scsi card
that came in the door, if the engineer was worth his paycheck, that
diode was replaced the first time the Amiga it was in, crashed. End of
problem except for one Trump Card, where in traceing that card, I found
the termpacks had been soldered in bass ackwards. It was easier to cut
and jumper the supplies traces than to unsolder the packs and turn them
around. So I did that in addition to swapping out the infamous diode.
We, in a middle 160's market, were the first to put our news on the air,
out as a webpage, which led to legal problems because CBS fussed about
their copyrights, so we had to filter any web content that came from
CBS, but that didn't last long after their bean counters discovered
there was money to be made. That was all driven by ARexx and delivered
by dialup from that Amiga in those Jurrasic (in web time) days.
Who am I to criticise the makers of that stuff? I have an 8th grade
diploma, but I am also a CET. Look that up if you care.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
--
ubuntu-users mailing list
ubuntu-users at lists.ubuntu.com
Modify settings or unsubscribe at:
https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
Mike -
Cer-Comp
5566 Ricochet Avenue
Las Vegas, NV 89110
(702) 452-0632
William E. Vergona wrote firmware on those two (2), 2708 ROMs.
He later (1980s) worked with Tandy (Coco-3) Color Computer products.
==
?68 Journal, May 1980 (Back to Future, 40 years later)
MiniDisk+ DOS , Pages 11 - 13
http://www.swtpcemu.com/swtpc/68MJArchive/V02N05_May1980.pdf
Have you contacted Bob Applegate (Corsham Tech)?
https://www.corshamtech.com/ss-50-faqs/
He might be aware of source from his SS-50 clients and contacts.
Bob reopened his business (Corsham) three weeks ago, for a period of time.
I did not see him at VCF Midwest, due to his health issues.
https://www.corshamtech.com/back-in-business-for-now/
Greg
Chicago
==
From: Mike Douglas <deramp5113 at yahoo.com>
To: cctalk at classiccmp.org
Subject: SWTPC 6800 and Percom Floppy Controller
I?m restoring a SWTPC 6800 that includes the Percom LFD-400 floppy controller. This controller goes on the SS-50 bus instead of the SS-30 bus where the SWTPC controllers installed. The standard Percom MiniDOS PROM is installed, and the other two PROM sockets have a third party extension called ?Minidisk+?. This was made by a company called Cer-Comp. These PROMs are instead of Percom?s own ?MiniDOS PlusX (MPX) PROM.
I?ve got the system working, and I can use Minidisk+ to save and load files, but I know I?m missing some nuances of command parameters. I don?t have any sort of documentation for Minidisk+, so before I go figure it out by disassembling the PROMs, does anyone have any sort of documentation for Minidisk+ by Cer-Comp for the Percom LFD-400 floppy disk controller?
Also, I?d like to burn the MPX PROM as an option. Does anyone have the MPX PROM or the source code for MiniDOS PlusX?
Mike
On Fri, 2020-01-03 at 12:00 -0600, cctalk-request at classiccmp.org wrote:
> On 1/2/2020 1:35 PM, Cameron Kaiser via cctalk wrote:
> > > > Anyone done anything with Netware *for PowerPC*? Allegedly
> > > > there was
> > > > some attempt at Apple to put it on what later became the
> > > > Network Servers
> > > > (the codename was apparently "Wormhole").
> > > I know the people who were working in it (based on Portable
> > > NetWare)
> > > AFAIK it never shipped.
> > Was this based on the Cygnus PowerPC port, or was it Apple-
> > specific?
> >
> Sun did a power? PC? port I think paid for by IBM, which would have
> run
> on both the open Apple servers that briefly existed, and on IBM PPC
> systems.
>
> A lot of odd PPC work happened in a group a friend worked for in
> Austin
> TX, but not sure if they did Netware work there.? There was a lot of
> OS2
> work there as well, but that's off track a bit more.
>
> thanks
> Jim
I was lead tech at a small computer company in Asheville, NC. in those
days. I ran OS/2 from version 2 in the early 90's to Ecomstation in
the early 2000's.
Does Talingent Pink sound familiar? OS/2 was ported to powerPC, and so
was Netware iirc. The field was quite busy with hopeful Microsoft
killers. OS/2 was to be morphed into a cross-platform o/s, to wean
folks from dos/x86..... Then PPC kills the x86 and we all get a decent
os. That was the plan anyway. I never saw OS2 for PPC or Netware for
OS/2, thought I know both to have shipped.
Jeff
Hi all,
I snagged one of these Nixie-like displays (from a calculator I assume) and
I'd like to light it up. Does anyone know where I might find the datasheet
for it? Google hasn't turned up anything.
https://www.ebay.com/itm/264110638970
Any help is appreciated!
--
Anders Nelson
+1 (517) 775-6129
www.erogear.com
Bitsavers has a schematic of the ANSI interface version of the Priam
3450/7050 eight-inch hard drives, but does anyone happen to have the
schematics of the "normal" version (Priam interface, as opposed to SMD or
ANSI)?
