There have been a few versions of the utility imd2raw.c floating around
that will take Dave Dunfield's ImageDisk-created images (i.e. an .IMD file)
and make a linear binary image devoid of any metadata. This is similar to
the function of Dave's IMDU.COM program's /b switch.
I've corrected a problem with the assumption that all imd2raw.c descendants
to date have made: sectors that have a skew (i.e. not 1-1 interleaved)
weren't linearized correctly. The skewed sectors need to be written out in
"sorted" order, which is not necessarily captured/physical order. This is
easily verified by comparing output from "IMDU /b" to earlier imd2raw
outputs on any .IMD that has a sector skew that isn't 1, 2, 3 [...].
It's up on github here:
https://github.com/RetroFloppy/imd2raw
Hello,
I'm an employee with the National radio astronomy observatory here in Socorro New Mexico.
As part of our NGVLA upgrades, we are seeking to get rid of old data tapes from the tape reel days of Computing. These contain things such as the boot loaders, OS, specific collection programs and antenna movement programs.
I personally would hate to see these just wind up in the literal dumpster and would like to see them sent out to a museum or an archiving body that can preserve them and keep them safe as a dynamic part of history.
If anyone is interested or knows someone who would be interested in the VLAs data tape library please let me know.
V/R
Danielle Werts
Front end engineer
VLA Socorro New Mexico
Hi there,
I need a power supply for my PDP8F computer.
It is missing.
The PDP8F 19" chassis box came in 3 different depths,
600 mm (PSU front to back)
370 mm (PSU across the back)
300 mm (PSU front to back)
I need the shallow one, the 300 mm PSU front to back.
Do you have one available, or know where I can get one please.
Even if it is dead!
regards
ray
Hi! Remember the blearrnnnnt-meeeeeelrp sounding seek oscillation noise
that the RD54 makes when you turn it on -- after it spins up, unlatches and
loads the heads?
Well, I took a chance on an el-(c)heapo ePay special RD54 that does all
these things perfectly up until the seek oscillation thing and then only
makes one steady meeee- sound that seems to last indefinitely (or at least
until I get tired of listening to it after a few minutes).
Would anyone here know enough about these disks to venture a guess at where
to begin troubleshooting this?
thx
jake
P.S. If I'm being too vague, let me restate: I can hear it spin up,
bearings sound normal, hear it unlock its head lock latch, then a perfectly
*slight* noise of head actuation and the normal accompanying barely audible
riding-on-air head noise. Then I expect to hear the two seek tones, but
only get one steady seek tone that lasts (I assume) forever.
Hi all,
I recently acquired a very nice decwriter III and it seems in good nick. However, the self test "hangs" on the return direction of the second line. Here is a video on it:
https://youtu.be/pj6rk5Dlnbk
Anyone have any ideas where to look? In local mode, it appears to work properly. I haven't tried any external serial connection yet.
73 Eugene W2HX
My Youtube Channel: https://www.youtube.com/@w2hx/videos
Hi Jon!
> think the Bendix G-15 had cassettes for the 5-level tape
> they used.
Aha, interesting! Did a short search, but have not been able to
find a picture of a casette. Just a pile of paper tape instead ;-)
https://images.app.goo.gl/HYqkpYHJUxZeGfiA8
> of mylar tape instead of paper. OS boot tapes might be punched
> on that.
Yes, for heavy use (and e.g. humid environments), the mil guys obviously
used Mylar or heavily oiled tape. Although not experrienced myself, I was
told that the Mylar tape cuts through the guiding pins of the readers over
time. And yes, it also may easily cut one's fingers ;-)
> much like plain paper tape, and simple mylar alone. The latter often
> comes metallized on one side, and is glossy.
Yes, that is the one within the casette and the aluminum as you expect
is for optical reading (Most plastics including Mylar are quite
transparent for IR light and in the old days, when thungsten bulbs
where used, the IR part of the light was the major part contributing
to the response of the photodiodes!
> input medium for the university mainframe computer (Electrologica X8),
> they used optical readers rated at 2000 characters per second.
Wow - that is indeed pretty fast!!! My FACIT is 1200cps maximum and
stopping "on character" as it is called is VERY hard at that speed.
But buffering helps here and in case of the 920M, the casette is
used for, there was no buffering. So software needs to be read in
one run.
Best wishes,
Erik.
''~``
( o o )
+--------------------------.oooO--(_)--Oooo.-------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
Hi Paul,
thanks for your answer and the interesting links...
> > Aha, interesting! Did a short search, but have not been able to
> > find a picture of a casette. Just a pile of paper tape instead ;-)
> >
> > https://images.app.goo.gl/HYqkpYHJUxZeGfiA8
>
> Bitsavers has a collection of G-15 manuals. For a picture of an
> open cassette, see PDF page 27 in http://bitsavers.org/pdf/bendix/g-15/60061400_G15D_Parts_Manual.pdf.
Ahh OK, I see. But that is not a hermetically sealed casette
suitable for outdoor use in windy, rainy weather like the
one on my desk.
As the thread deviated meanwhile, I guess the Elliott Mylar
tape casette is a unique leftover from the old days ;-)
Best wishes,
Erik.
''~``
( o o )
+--------------------------.oooO--(_)--Oooo.-------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
Hi there - recently I posted a small video on a rugged
paper tape casette...
https://www.youtube.com/watch?v=O2jnThYsPKc
I wonder whether anyone kows if someone else had the idea
of putting paper/mylar tape into a casette for repeated use
e.g. to load an OS or similar.
Best wishes,
Erik.
''~``
( o o )
+------------------------.oooO--(_)--Oooo.---------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +----\ (----( )-----------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
I have some 8-bit ISA 53c90a based SCSI controllers labeled "SCSI HB A8".
Mine are made by "Advanced Information Concepts", but apparently they were
also made by "Control Concepts". Unfortunately, mine don't have the BIOS
chips installed. I have a picture of the card with a chip installed
labeled "Ver-3.02 CCI 0991", so I know an 8k or 16k boot prom existed.
Does anyone have such a card that they'd be willing to dump a prom image
from (or let me borrow it to dump).
KJ
A bit of an odd one….
I’m trying to figure out what type of computers ran Mexico’s infamous SNIPE
electoral vote system in 1988. I have an LA Times article from 1994 talking
about how the NEW system was RS/6000-based. But this was a system built in
1987-1988. Narcos Mexico had a pretty re-creation but I didn’t spy any
brand names. Any ideas? I figure there may be photos or press releases from
that time but my Google-fu (and español) is weak.
-Jon
+44 7792 149029
