Ethan won the "out-of-the-way-corners-of-the-earth contest" on Velonews
(competitive cycling magazine following the Tour de France).
and, if they decide to start an "insane readers" contest, they assure
him he's in the running as well.
has anyone got a early copy of the SCSI spec which just covers SCSI 1
(i.e. 8bit bus, 5Mb/s transfers only)?
I want to see if I can get the parallel port on a modern PC hooked up to
one of the old SCSI/ST506 bridge boards that I have, but given that I
only have 12 data out lines to play with and 5 data in (13 in if I
assume a bidirectional port) things are pretty tight and I obviously
need to do some loading of stuff into external registers.
I've got some reasonable info on the SCSI protocol, but having a better
idea of which signals do what (and at what time) would be useful.
All the docs out on the web seem to be for the latest SCSI revision
though (and therefore contain a lot of info that I don't need).
Furthermore I only really need the low-level protocol now;
software-driven higher level command structure can wait for a few days!
On Jul 28, 12:11, Joe R. wrote:
> The problem is that AFIK no one has found ANY CD disks that are
> reliable. Several people that have been interviewed in national
> publications explictly pointed out that they bought top quality disks
> they were still unreliable. In fact, it didn't appear that there was
> difference between the cheap ones and the expensive ones.
The other day I came across a table from a report showing the relative
longevity of data on various media (DLT, CD-R, etc) at a variety of
temperatures and humidities. I'll try and find it again and post some
of the results. Some of you might be shocked. For example, a CD-R
with an expected lifetime of something like 25 years (if I'm not
misremembering the highest figure) under ideal conditions has a
lifetime of only several *months* at higher temperatures (upper 20s C,
that would be 80s F) and humidity. DLTs fared much much better.
I have some CDs that were bought about 8 years ago because they were
supposedly good quality, and burned in a highly-rated burner. Out of
the first batch of ten, 4 are now unreadable or give multiple errors.
Pete Peter Turnbull
University of York
Does anyone know what was the first computer to have a built-in real-time
Sellam Ismail Vintage Computer Festival
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
I am considering having an exhibit at the next Vintage Computer Festival (7.0). I was wondering what the security is like for the exhibits. Do you need to packup up each night? I would like to here comment from those who were there (Computer History Museum) last year.
Now that I'm back on the list, by dint of unsub + resub (which I really
should have thought to do earlier, rather than waiting against the time
Jay finally emerges from the aftermath of VCF East)....
I'm trying to build a KA630 emulator, more because I think it'll be fun
and will teach me stuff than because I actually have a use for such a
thing (there are plenty of good open-source VAX emulators out there
already). I picked the KA630 because it's the only VAX implementation
I have enough information on to even really attempt to build a
I dumped the ROMs from one of my KA630s (e/l/p/n:3fff 20040000, plus
some postprocessing of the capture file) to get firmware. But the
emulated VAX hangs at selftest step B. The manual I have
(EK-KA630-UG-001) says this means that the IPCR is not working properly
(probably broken Qbus electronics, on a real KA630), but it doesn't go
into any significant detail.
Furthermore, if I break to the simulator and manually advance it past
the "blbc r0,." that it's hanging at, it continues, but ends up with an
error at step 7 - apparently it can't find any working memory(!).
Now, the manual could be simply wrong. I've found it lying (or, let me
be charitable, "not matching the machine I have") at once already; it
claims certain bits are write-only, but the ROM code depends on being
able to read them.
Or I could be mis-emulating the Qbus stuff.
Or I could have a bug in the emulation of an instruction somewhere.
So, I'm looking for either or both of (a) someone who's enough of a
KA630 guru to help or (b) some kind of VAX instruction-set test suite,
to help verify that I have the instruction emulations right. (I caught
one instruction emulation bug already, quite by chance; there is surely
at least one more.)
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If you guys are intending to build a Z8000 machine to
run CP/M-8000, you should let me know. There are a couple
hardware restrictions you should know about early on.
>From: "Kane, David (DPS)" <David.Kane(a)aph.gov.au>
>The Z8000 segmented address scheme has two forms. The long form that you
>described uses two 16 bit values (registers or memory locations). The
>short form uses a single 16 bit value with the 7 bit segment number in
>bits 9-15 and an 8 bit offset into the segment in bits 1-8. Bit 16 of
>the first 16 bit value is a flag which indicates long or short segment
>address. This is important for memory addresses operands as the CPU can
>get an address word operand from memory, and then based on the flag bit
>can decide if the next word must be read to get the complete long
>address. In either case the segment address is located in the same place
>in either a short segment address or the first word of a long segmented
>> -----Original Message-----
>> From: cctalk-bounces(a)classiccmp.org
>> [mailto:firstname.lastname@example.org] On Behalf Of SHAUN RIPLEY
>> Sent: Monday, 26 July 2004 1:27 PM
>> To: cctalk(a)classiccmp.org
>> Subject: z8000 segment scheme question
>> I picked up one of my computer books today and read
>> that z8000 uses one 16 bit register to hold the 7 bit
>> segment number and one register to hold the 16 bit
>> offset. The strange thing is that the segment number
>> is hold in position of bit 9-14 other than the bottom
>> half of the first register. I goggled and found
>> complaint about this scheme but no one explained why
>> it was designed so. Could somebody on the list tell me why?
>> Do you Yahoo!?
>> Yahoo! Mail - 50x more storage than other providers!
Vintage Computer Festival <vcf(a)siconic.com> wrote:
> > If you mean a clock that maintains time when power is off or gets the time
> > by radio then we are probably into the micro era.
> But I can't imagine there was not a real-time clock (i.e. as described
> above) as at least an option for an earlier computer system.
VAX Architecture Reference Manual requires every VAX to have one,
and they all indeed do starting with the 11/780. Was the 780
introduced in 1978 or 1979? In any case it was designed in the late