<have something concrete in mind, too. If one inserts a wire-wrap 62 pin
<(8-bit ISA) connector into a DIN 41612 right-angle socket, such as what on
<finds on a VME wire-wrap board, but of opposite gender, (remembering that
<once sold S-100 wire-wrap boards with a pattern certainly suitable for thi
<purpose, and VME wire-wrap cards as well) one can, indeed, host two 8-bit
Been there and done that. Also there are no less than two articles on how
to go from s100 to ISA.
<ISA cards on a single s-100 board. This would certainly be cheap enough i
<most cases, to warrant such an effort. The software might get to be a
<problem, though.
What software problem... since s100 cards tend to be all different anyway
it would be the norm that software would have to be created.
Allison
<memory mapping would be a mite silly, wouldn't it, given that the HERC use
<64K of refresh RAM. I'd say the way to do it is to use a strategy put fort
No, you partition in to 16k quads and your off.
<by the guys who designed the 6545, the '65xx' version of the 6845. It had
<an update register which essentially allowed you to write an address to th
<chip and then send a stream of characters, kind of like the cursor
<addressing on a terminal.
Run a kaypro some time... slower than sludge video.
<Some scheme like that would work even in the limited I/O space of a Z-80.
<Another option might be to bank the BIOS such that when it's writing to or
<reading from the video page, it has a space equal to the disk buffers, whic
<works as a window in the display RAM. The refresh of the display would kee
<the entire video memory refreshed, while the banking scheme could minimize
<the memory consumption of the video device.
Full circle. Hence the need for a MMU. Me I'd never use the 6845/herc in
graphic modes. For text the Herc cards only need 4k.
<The PC certainly has made for cheaper serial/parallel interfaces than we
<ever saw for the S-100. It's too bad there were never any truly general
Volume will do that.
<purpose parallel ports use commonly enough on the PC to make them cheap.
<It's only since the adoption of the 1284 standard that bidirectional I/O vi
<the printer port has been practical. It's too bad there aren't
<i8255-equivalents which can drive something. The problem with my IMSAI
<PIO-6 is that it won't even drive an LED directly.
That's why things are buffered. the 8255 will drive a few feet of ribbon
but generally thngs like ground loops and other anomolies make a buffered
interface more robust. At the time of the 8255 heyday the output current
was limited by the Nmos process of the time to only a few mA. Now, the
CMOS processes can easily do 30-70 mA but... you can still fry them.
Allison
Hello everyone,
Last week I bought a pile of hard-sectored 5.25" disks. Most are used,
but are still in their original plastic box. Most disks have a lable
saying: AES diskette, Single Sided, Single Density.
Since I'm an Atari 8-bit freak, I don't have a real use for these,
however they can be used on 3/4 of my diskdrives since these do not use
the index-hole for anything. Someone in an Atari usegroup asked me to
write a msg over here before starting to write Atari-data on them. I
have some CP/M's laying around, but they seem to work well without the
use of hard-sectored disks too, so.... If someone wants them, I'll
swap them for anything ATARI-related. If not, I'll just format them,
and write Atari 8-bit data on it.
Would be nice if someone could pick them up in the south-part of the
Netherlands. I have no idea what it would cost to send them by
snailmail, cause I have more then 200 of them.
please note: I'm not subscribing to this newsgroup, so Email me at:
"fox-1 AT aq DOT nl"
Sysop Fox-1, Thunderdome, ATARI 8-Bit BBS,
+31 416-279990 (21:00 => 8:00 CET)
Hi again,
I conscripted my father to come and help me drag the AES 7100 home today.
It doesn't work. The display powers up but nothing is displayed. The
drives never turn but their lights shine at the instant the power switch
is flipped. I suspect its not working has something to do with several
empty sockets on the motherboard, but I can't be sure.
Even with it not working, it's an interesting machine.
It's a little over 26.5-inches wide, and over 16-inches deep if you
include the handles on the back for pulling out the motherboard. The main
box is about 4.25-inches high, with a 10.5" green phosphor monitor sitting
on top of it, connected with a swivel neck. The top of the monitor sits
about 16" above the surface of the table. The disk drive portion of
the box is about 10.5" high and 9.25" wide, and is visually disconnected
>from the rest of the box in the same way that an Apple III keyboard is
visually disconnected from the rest of the III... still built on the same
metal frame underneath.
The motherboard pulls out on a tray from the back of the machine, with
only two screws holding it in.
There are numerous holes for ports of various sizes, but most of them have
metal plates screwed over them and nothing behind them. Unscrewing the
plates usually reveals a picture of a telephone handset beside the hole.
There are plenty of post holes in the motherboard in locations that match
the holes in the back of the case, so there must have been plenty of
options.
My own machine only has one small daughtercard sitting on posts, with a
50-pin male edge connector accessible from a hole with a drawing of a
printer beside it.
There is also a 12-pin female port with a drawing of a printer beside it,
with the pins arranged in a 3x4 grid.
On the motherboard, there is a Mostek Z80A, probably 4MHz. There are
three Z80A PIO chips, and two Z80A CTC chips, and several other large
multi-legged critters.
There are three 8-chip banks of 4164 DRAMs, with a fourth row left empty.
That's quite a bit of memory for a Z80!
There is a 24-pin EPROM, with an empty 24-pin socket beside it.
There is a set of two other 24-pin chips which might be ROMs.
There are two other empty sockets, one with 18 pins and the other with 16
pins.
There is a 15.something MHz crytal, and a 24.0000MHz crystal.
There is oodles of TTL.
Chips range in dates from '79 to '82.
The keyboard connector inside the machine is cracked and broken and won't
stay in place.
The keyboard is larger than it has to be, with lots of photogenic
whitespace around the key areas.
The area that would normally be a numeric keypad on a normal keyboard has
pictograms of unknown function.
The key which must be the caps lock lights up when it is hit, but the
light doesn't turn off if you hit it again. It only turns off when the
keys which must be shift keys are hit.
The disk drives are full-height, single-sided.
It has a plate with "7100" on the front, but a small plate on the back
says "AES Model 203".
The monitor has no external controls, but there is what appears to be a
trapdoor on the back of the monitor which is screwed shut. Perhaps I
should try messing with that before I decide that the machine is
definitely dead.
There is another machine just like it at the same store, even grimier than
this one was. But considering the hassle of hauling and storing this
thing, I don't think I'll have the energy to go back for it.
--
Doug Spence
ds_spenc(a)alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/
Status report:
I've rebuilt the power supply. This was done after the following steps:
Open PS and remove the bad rectifer bridge and shorted 24,000MFd
cap.
Vacuum out all the decomposed foam.
Put boards (all but core) and regulator board in dishwasher and
dried them in the oven.
Reassembled and tested power supply in stages. Working.
Replaced three fans.
No I have the system up and running save for one bit that is stuck (when
displaying MD). The display bit is stuck as test programs run verifying
it's a front pannel problem. It's bit 1 and only with the switch in the
MD position.
So far this is good success considering the heaviest test gear used is a
multimeter. Also that I don't have a print set for 8E.
Allison
What might be fun would be an S-100 card to serve as an interface to a
Monochrome/Hercules equivalent card and an IBM-style keyboard, since these
can be had complete with the rest of the computer for $5 at nearly any
thrift store. That would save the hassle of having an extra keyboard and
monitor for your "extra" PC. . . . . you know, the one you stick strange
cards in in order to see if they cause the system to "HCF" (Halt and Catch
Fire). One of those little switch boxes would serve just fine. The 8.0 MHz
Z80 wouldn't be sufficient to drive a VGA, so no need for anything fancy.
It could even support two short ISA cards.
Dick
-----Original Message-----
From: Allison J Parent <allisonp(a)world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Saturday, April 03, 1999 6:26 PM
Subject: Re: homemade computer for fun and experience...
><IF you can stick the XT keyboard (are keyboards that talk that protocol
><still being made?) then look at the circuit of the PC or XT. The keyboard
><interface is a few TTL chips hung off an 8255.
>
>At keyboards can be used as well as they are similar (not the same).
You'll
>have to make a interface as the serial is not compatable with UARTs, also
>you will have to convert the key down/Key up codes to something more human.
>
><I'd make it modular (in that I'd have expansion slots), but I'd probably
><put the CPU + RAM + basic I/O on the 'motherboard'. For prototyping,
><DIN41612 connectors are easier than edge connectors because you don't
><need special boards with the connector fingers on them.
>
>An acceptable bus is ISA-8bit and there are plenty of FDC, VIDEO, HDC cards
>for that bus that could easily interface to z80.
>
><SRAM is a _lot_ easier. And now that 64K SRAM is 2 chips at most (62256's
><are cheap now), I'd use that. DRAM is not too hard until you realise that
><layout and decoupling are critical if you want to avoild random errors.
>
>Same comment, one proviso, if your doing over 256k consider DRAM and MMU.
>a good article for that is at the TCJ site.
>
><[For the hardware wizards here : Yes you can homebrew with DRAM - I've
><done it. But not as my first real project].
>
>For a z80 system of 64 or 128k static is far easier. Also 128kx8 parts are
>cheap so even 256k or 512k ram systems are modest.
>
>Allison
>
> Wait... will RLV11s go in the 11/44??? That would be major cool,
>as well...
No, RLV is for Qbus... generally, if you find an option which has
a Q or V as the third letter in the option name, it is for Qbus.
For example, dlV, dhV, dhQ, dzV, dzQ, vsV, etc...
Some options for UNIBUS have a U as the second or third of
the option name... dhU, dU. But generally, the UNIBUS options
are two-character names, DL, DH, DZ, VT, etc... As always, there
are exceptions, like DUP, DMC, DMR...
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
>Zane H. Healy wrote:
> >I'e done it with both using the correct backplanes. As I remember the
> >SMS1000 is a bit strange in the boot deperatment.
Jerome Fine replies:
>My box has a single 8" floppy which is DSDD in capacity for a total of
>1976 blocks. The drive is also set up the detect SSDD floppy media
>as well as DSSD and SSSD media. BUT, the device type is for the
>MSCP emulation. AND the DSDD interface switches from side 1 to
>side 2 for each cylinder (or track since there is only one double-sided
>surface) within the firmware. Since this behaviour is outside the control
>of the device driver (MSCP is DU:), the use of DSDD media is quite
>a surprise as compared to the RX03 implementation on a DSD
>880/30 which uses the same floppy media, but uses the whole first
>side of the media followed by the second side of the media as
>programmed within the DY(X).SYS software device driver in
>RT-11.
These block-numbering issues are addressed by Chester Wilson's
"DYC" handler, to an extent. To quote from the documentation:
*This handler is designed for Sigma/Dilog RX03 controllers, with optional
*assembly for DEC, MTI, and DSD ones. It may need minor modification
*(notably to the extended addressing and formatting code) for other
*manufacturers' boards.
*...
*In version 4, support for the SMS flavour of RX03 format has been added
*(courtesy of discs from Billy Youdelman).
Sources to this code are available at
http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/rt/bill…
This code also knows how to format completely blank floppy disks into
DEC-compatible RX01 or RX02 on many third-party controllers under RT-11/TSX.
>As soon as I finish my tax returns and clean up a few other
>things
Don't you have till April 30th up there? (I have to get the
Canadian forms for the money I earned in Canada last year, still...)
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
>Geez! Trade em some more modern hardware for what you want/need. I've
>been giving away lots of Mac IICi's for the last 2 years now, since
>the university here keeps throwing em away. Another department here
>has been trying to sell mac IICi's for $15 each, and it doesnt look like
>they are selling em at that price.
>
Where are you located? I wouldn't mind getting one of those Macs. My
church has also been looking for a couple old Macs for their education
center, since there's a Mac guru that goes to my church (anyone need System
7.5 or System 7.5.x updates??)
>I dont have any TRS-80's in my collection (except one mutant model 4),
>and if they have any REAL apple II's (ie, not a plus model, the real
>integer basic II's), it would seem to be a nice trade.. I imagine
>they would love a 486 system, or even a good 386, if all they have
>are TRS-80's and Apple II series computers.
>
I think They have a couple that they use (at least they did when I went
there) for their card scanner (for bubble-sheet tests). The only TRS-80
that I have is a fried Model III that I've gutted and am trying to convert
it using some old Tandy 1000 parts (anyone know how to connect a TRS-80
monitor to a CGA or composite output?)
--
-Jason Willgruber
(roblwill(a)usaor.net)
ICQ#: 1730318
<http://members.tripod.com/general_1>
>-Lawrence LeMay
>lemay(a)cs.umn.edu
>
