Tom Peters wrote:
SCSI drives often have a spin-up jumper, so that the machine can spin them
up one at a time to decrease inrush current caused by large arrays spinning
up all at the same time. Some drives also have a spin-up delay jumper-- 1,
2, 4 or 8 seconds. Others switch on the motor on first access.
On many drives, the jumper(s) are on the bottom.
I never heard that these lines are brought out to the interface, but also I
never heard that they're not brought out.
Perhaps that's something to do with it.
-------------------------------
Billy wrote:
In the early days of SCSI, spin delay was not standardized. There were
several versions. One used a fixed delay, like you mentioned. But the most
common delayed a fixed number of seconds multiplied by the drive ID number.
So unit 3 would be 3X delay, LUN 4 would be 4X delay, etc.
This was a holdover from the SMD days. SMD drives would delay until the
unit in front of them on the cable went ready. So a string of drives would
come up one at time. The unit number times a fixed delay was an attempt to
speed up the process. The problem only occurs on the initial inrush to the
motor. And that current drops rapidly once inertia is overcome. The
engineers realized that they didn't have to wait for ready, only until the
current dropped to a normal level, usually only 1 or 2 seconds.
Billy
In case anyone is interested, I have added a new
utility to the Imagedisk package called DMK2IMD which
converts a DMK format image into an ImageDisk compatible
image (.IMD). Let me know if you have any problems.
If there are other floppy disk archival formats that
anyone would like to see supported, please let me know
and I'll see what I can do.
Regards,
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
now ain't that subject line an attention grabber. Not
exactly what you'd call a Mac related topic...at least
not so much to me. But simply an opportunity to
appreciate a particularly rare, exceedingly beautific
(arty?) piece of vintage crappola. I posted this in
the Tandy 2000 Yahoo group a few hours ago and thought
I'd share it with the remainder of my faithful
followers on this list. Yes your gratitude is well
received.
You can view the subject of the thread here:
http://groups.yahoo.com/group/Tandy2000/
you don't have to join, but what would be the reason
not to???
my gosh it's soo beautiful *snifful* I can barely
stand it ...
I'm referring to the picture of the Xerox 16/8 I
placed on the front page. I challenge ANYONE to find a
more luxurious looking vintij puter.In reality, that
box isn't the "puter" at all, but the drive expansion
unit. The computer logic is embedded in the monitor -
the
Xerox 16/8 proper. It has an 8086 and a Z80 for the
best of those worlds (but no it's not peecee
compatible, but that sure done didn't make a
difference back in them days. Nuh uh. We all bought
puters like
it, and lived to tell the tale...).
My particular 16/8 is in exceptionally good shape,
but I believe the hard drive is bad. When I had
learned of it's existence I guess 2 years ago (that
guy in N.Carolina, uh vintagemicros? had one up for
bidding, w/the caption "Insanely Great!", no doubt
trying to cast it as a Macintosh predecessor (cpu and
crt integral sparky)), I did a search, and found a guy
w/one in Maryland. The origins of the Mac are
not estranged from Xerox corp. I guess, but the
resemblance between a Mac and the 16/8 is somewhat
hard to define other than what I pointed out. I rather
suggest the caption should have read "Insanely
Stoopit!" LOL LOL LOL LOL LOL
A thoroughly beautific piece of vintage garbage
though wouldn't you say?
____________________________________________________________________________________
Food fight? Enjoy some healthy debate
in the Yahoo! Answers Food & Drink Q&A.
http://answers.yahoo.com/dir/?link=list&sid=396545367
I just discovered a flaw in my DMA setup sequence which exposes
a timing window during which bus noise can cause false dma
events (DMA enabled but FDC not driving it yet), leading to
ImageDisk not working correctly in some PCs.
I have corrected this (with the help of a couple of very knowlegeable
list members - thanks guys!), and released an updated ImageDisk 1.16
with the fix.
I have also updated the source code archive to include the new
TESTFDC and .TD0 conversion utilities.
Enjoy,
Dave
PS: I found this while fooling with and old 486 because I finally
decided to see if I could get my Central Point DEluxe Options Board
working - the TRANSCOPY that I had for it wouldn't run at all (froze
during the analyze phase), but I downloaded one from the net which
does, but I have been unsuccessful in actually recording and
recreating a plain-jane DOS DD 360k disk - I've gotten it to complete
the motions a couple of times but the result has errors in it.
This is a 486/25 (slowest I could make it) - does anyone know if
the CTP board will work reliably, or do I need to go slower...
Any other common causes of problems...?
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
> And what modern *nix ports, if any, do other list members use on
> their classic iron?
I ran it on my VS3100, Alpha PC64-275, various MIPS & ARM gear, Sun 3 &
SS20, MVME 680[346]0, VME PPC, and Xen & x86 (not classic). I still have
1.5 on a PC532 and run current on Xen & x86, having gotten rid of everything
else (well...the VME stuff is in storage pending a decision on keeping it).
From: Sridhar Ayengar <ploopster at gmail.com>
> Where did you manage to dig up a PC532? Or did you build it yourself?
I purchased the original kit from Dave & George. However, this one isn't
it. My original, partially built kit got accidentally tossed in a breakup
something like 15 years ago. There was wailing and gnashing of teeth.
A couple of years ago, I mentioned that I was interested in ns32000 gear and
got an email to the effect "I've got some of that, make me an offer". A bit
of cash later I had the PC532, an ICM3216, a custom built ns32332 unit and a
Heurikon VME532, along with some doco and a bunch of extra parts.
Pretty decent haul.
Ken
> and what about the 68000 version of Windoze NT?
Not possible.
NT required a little-endian processor.
A PPC version existed. The processor was in little-endian mode to run it.
>Henk wrote:
>I still want to get my TC11-TU56 online, but my 11/84 is
>giving problems with the RL02 drives. Need to fix that first.
Is your 11/35 still alive and well? I thought you had the
TU56 hooked up to your 11/35 in that massive chain of
H960 racks.
I recently acquired an 11/35 in a rack with an RK05J and
an RK05F. It has some life in it, but is not behaving
correctly. Some bits seem to get stuck when I run tests
depositing and examining memory. I am in the process of
validating some of my spare 11/40 CPU modules. Hopefully
I have enough good spares to get the 11/35 up and running.
Ashley
>
>Subject: Re: Some progress with my PDP-11/73 system
> From: David Betz <dbetz at xlisper.com>
> Date: Tue, 10 Apr 2007 08:17:49 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>> RD53s are notoriously unreliable, but I'm surprised that four out
>> of five simply aren't detected. Are they genuine DEC RD53s? You
>> need to add a PCB link to an ordinary Micropolis 1325 or 1335 drive
>> to make it an RD53. Look on the PCB for the location marked R7
>> (remove two screws and carefully hinge it up) -- if there's nothing
>> there, solder a link in that position. Oh, and don't use a skid
>> plate with bare metal with an RD53, as it can short things out.
>
>Three of the four failing drives were official DEC RD53 drives as
>indicated by a sticker on the top. Interestingly, when Iooked at R7
>on the PCB, two of them had the resistor present but one end had been
>cut. I soldered it back together but both drives still fail. At least
>one of the drives spins up but then back down again. I'm reluctant to
>try swapping the PCB between my only working drive and one of the bad
>ones so I think I'll just count them as a loss.
The one that pinsup and then spins down has the head bumper sticking
problem. That is repairable and likely the HDA and logic is good.
Me I'd repair that drive and use it.
Allison
>Henk wrote:
>I still want to get my TC11-TU56 online, but my 11/84 is
>giving problems with the RL02 drives. Need to fix that first.
>
>Is the H720 the power supply inside the TU56 chassis?
>ISTR that you need an external power supply, +5 or +15 comes
>to mind, and there are two voltages possible, but only one
>must be connected ... I could be totally wrong.
>
>The first thing I must do is a check if all FlipChips in the
>TC11 are at their correct position, and if all are present...!
>
>Following this thread with argus eyes :-)
>
The H720 is a separate power supply and is not part of the
TU56 chassis. It has (IIRC) spade connectors to run the
various voltages to the TU56/TC11. I have hooked up the
TU56 to the H720 to test it out in standalone mode.
If I am able to escape from "she-who-must-be-obeyed" tonight,
I plan to make some progress on this project. I'll keep
you posted!
Ashley
