On Fri, 7 Feb 2014, David Gesswein wrote:
> I did a little searching and some IMI units use a non ST506 interface so
> without changes my unit can't deal with them. The IMI 77xx are neat
> looking drives.
Indeed; 8" platters, a 'real' voice coil and a transparent cover to let you
watch the action. As a matter of fact this weekend I'm planning to see if I
can revive a 7710.
---
On Fri, 7 Feb 2014, Steven Hirsh wrote:
> Corvus used the IMI 5006, 5012 and 5021H depending on the storage
> capacity. From everything I can see, these are (or should be) plain
> vanilla MFM drives.
That's interesting; are you sure that 5021Hs are ST-412 drives? The 5021H
drives that I have all have the IMI interface and almost definitely came
>from the factory that way.
Some of the 5 1/4" IMI drives were available in both versions for a while,
with the IMI interface or the ST412 version (as well as a custom 'raw'
version) and conversion kits were even available, but I always assumed that
the original model numbers would be different.
FWIW AFAIK their first 5 1/4" drive was the 5007, unusual in that it was in
a plastic chassis and used an external optical index sensor; many fond
memories of having to clean out dust and realign without losing client
data...
I also have an IMI interface 5018H but don't recall what its specs are.
> The more I think about this, the more I think they've taken some pains to
> ensure it will only work with IMI drives - maybe some sort of special
> operational mode?
I'd be surprised but it's certainly possible; Corvus and IMI were closely
connected ever since Corvus began with an 8" 77xx-based hard drive cabinet
for the Apple ][, and in fact they ultimately merged.
Hi,
I've just got (another!) AT&T UNIX PC keyboard to replace the one with
missing keycaps and -- woe and behold -- this one has a few dead keys!
For bonus points, it doesn't use the same switches as the other
keyboards: it uses ITW "Magnetic Valve" keyswitches instead --
Details here:
http://deskthority.net/wiki/ITW_magnetic_valve
Photos here:
http://deskthority.net/keyboards-f2/reverse-rubber-dome-switch-t449.htmlhttp://park8.wakwak.com/~kaineko2/keyboard/album20110107.html
These switches were apparently used in Decision Data, Aydin and Devlin
keyboards, and consist of two metal pins and a tiny ferrite in the top
of the black keyswitch base, and a pink plastic key which houses a large
chunk of ferrite. A small chunk of rubber inside the keycap forms the
spring which returns the key to the "not activated" position.
The problem I have is that the ferrites on several of the keys have
broken in transit... with these being delightfully obscure and
apparently obsolete, my chances of repairing this thing (without parts
at least) are slim.
Does anyone have any of these keyswitches kicking around in a spares
box, or a scrap keyboard which uses these keyswitches?
Thanks,
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
Hi!
We are about to do another run of our popular S-100 Bus Z80 CPU V2 board.
This board can run in systems (with bus termination etc.) at up to 10MHz.
Apart from all the then common features found on many older S100 Z80 boards
(and being completely S-100 IEEE-696 compliant), it had an extremely clever
and powerful ability to allow the Z80 to address up to 1 MG of RAM in 16K
"windows" within the Z80's address space. This is described here:-
http://www.s100computers.com/My%20System%20Pages/Z80%20Board/Z80%20CPU%20Boa
rd.htm
Its primary importance is that it can be used to address greater than 64K of
RAM for CPM3 and that it can be used to load/examine 8086 code at the top of
the 1MG address space.
The new "V2" version of the board now has the ability to (under software
control) dynamically switch between two 4K blocks of code in its onboard
28C64 EEPROM (or EPROM) yet still only occupy 4K in the Z80's 64K memory
space. This in effect almost doubles the size of a possible Z80 monitor.
The extra code (currently being written) will include things like directly
downloading binary files from a PC into the Z80's 64K (or 8086's 1M) address
space.
In addition, the S-100 Z80 CPU V2 has the ability to use an external CPU
clock from an external source (S-100 bus pin 66 aka NDEF3). This is
essential for CPU to video synchronization for MSX compatibility
particularly in games. There will be a corresponding ability to export a
CPU clock signal on the next version of the S-100 VDP board although this
could come from any S-100 board.
Current owners of the V1 board can just switch the IC's to this new bare
board.
The S-100 Z80 CPU V2 PCBs will be $20 each as per the usual arrangement.
Shipping in the US is $3 for a single PCB and $2 for each additional PCB.
Shipping internationally is $12.75 for a single PCB and $3 for each
additional PCB. This is for the bare basics USPS first class postage with
no tracking or insurance. The builder assumes all risk of delivery as per
usual arrangement.
My preference is to sell these PCBs to vintage computer/home brew
computer/classic computer hobbyists first but if there are any remaining
boards I will put them on eBay.
Please send a PayPal to LYNCHAJ at YAHOO.COM with the subject "S-100 Z80 CPU V2
board" and I will reserve your board(s). I need about 20 pre-orders to
warrant a manufacturing run. I will post more information as it becomes
available.
Thanks and have a nice day!
Andrew Lynch
On Sat, 11 Jan 2014 16:14:31 -0800, "Mark J. Blair" <nf6x at nf6x.net> wrote:
[snip]
>
> * I'm having trouble finding 1" wide paper tape for my machine. It came with a small bit of black paper tape, and I see a single expensive roll of dark-colored 1" tape on eBay. I'd like to get a few rolls of plain old oiled paper tape in 1" width with a 2" core. There are several listings for narrower tape on eBay, but I'm not seeing the 1" width that I need. I'm looking forward to filling that chad box...
>
> * Last, but not least, I will naturally need a suitable computer such as a PDP-8 to go with it! :)
>
[snip]
>
> --
> Mark J. Blair, NF6X <nf6x at nf6x.net>
> http://www.nf6x.net/
Mark,
Try westnc.com at http://www.westnc.com/paper-tape-rolls.html#tty for
papertape. They have both oiled & unoiled 1-inch paper tape, but
recommend the oiled tape for ASR 33s. A 1/4 case of oiled papertape
(7 each 1000-foot rolls) may be affordable to you at $92 plus
shipping. (And they have rolls of paper for the Teletype's printer
too at $112 for a case of 12 rolls, plus shipping.)
Good luck on finding a PDP-8 to go with it though. :)
Bob
anyone herd of it never been able to find any info on it anywhere
its on 1inch paper tape
http://www.flickr.com/photos/85758861 at N00/6109885397/in/photolist-aiUL4F-dWX6HA-9fBJJ8
> 1) Gold edge fingers increase the board cost. Would people prefer a cheaper
> board with .1 headers like my wirewrap board that will need non standard
> cables or proper edge connectors for the drive emulation?
Well worth the extra expense, in my opinion,
as long as it will hold up to repeated insertion/ejections,
as already mentioned in other posts.
Would it be extremely difficult to put in a set of .100 holes
onto the board, a little bit behind the card-edge connectors,
so that folks could add their own header, if desired?
> 2) It might be possible to make the board emulate two drives. The
> system would have to be setup to use daisy-chained control cable since the
> board will only have one control connector and two data connectors. The second
> data cable would have to be .1 header. Is this enough interest to people
> to be worth trying to do?
TWO drives are always better than one. ;-)
Would each drive be forced to the same geometry / drive types?
T
An acquaintance of mine is looking to hook up his Heath/Zenith LSI-11 system to his H/Z-29 terminal. The system has the Sigma Information Systems 400200 interface card. I found him a copy of the manual but before attempting to build his own cable he was wondering if an existing cable might be found for RS-232 operation with this card. Any ideas on a source for something like that?
- Glenn
>
>I have a working VAX 4000-200 and bought a spare CPU board for it. I plugged
>in the spare board and it seems to hang when starting the OS boot process.
>I've included the log below. I looked through the KA660 technical reference
>and couldn't find what might be hanging at this point in the boot process.
>I'm assuming that I can simply boot from the same OS image as the original
>CPU.
>
Assuming you are using VMS, no changes are required to the system disk. In
fact you should be able to use the same system disk to boot any of the
various different VAX processors supported by the version of VMS installed,
not just a 4000.
>
>I compared the few jumpers on both boards and they are the same. I even
>validated the EPROM contents to be the same. Is the spare CPU board bad or
>is there something else I should be trying/aware of?
>
I guess DIA5 is the correct disk to boot from as you appear to be typing
it manually at the >>> prompt rather than relying on whatever is stored in
NVRAM on the replacement board which is probably incorrect.
>
>You can see from the
>log here that it does in fact pass all it's tests. Any help would be
>appreciated before I attempt to return this otherwise great looking board!
>
>KA660-A V3.7, VMB 2.12
>Performing normal system tests.
[successful tests snipped]
>Tests completed.
>>>>boot dia5
>(BOOT/R5:0 DIA5)
>
>2..
>-CAP05$DIA5
>
>
>Normally at this point you get a "1..0.." and then it boots into the OS. But
>with the spare board, it just hangs after the last line shown above. The
>EPROMs on both boards are identical as is the board revision and all part
>numbers.
>
I have a VAX 4000/100A but I use a SCSI disk to boot it as both my DSSI disks
have died. The disk I use fails to spin up sometimes after it has been left
idle for a while. When this happens, my 4000 hangs at the same point as you
are seeing. There are several short buzzing noises when the disk attempts to
spin and if I lift it up and give it a sharp twist at the time that it tries,
it usually starts spinning and all is well.
I don't know if this is also a possibility with DSSI disks but it seems
plausable. Is the problem still there if you put the original board back in?
Regards,
Peter Coghlan.