>
>Subject: Re: Hand-rolling a CP/M machine
> From: Warren Wolfe <wizard at voyager.net>
> Date: Tue, 24 Apr 2007 15:13:32 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On Tue, 2007-04-24 at 12:21 -0400, Allison wrote:
>
>
>> Another equally sneeky/sleezy trick was to force NOPs (00h) on the buss
>> till you hit the rom address where you disable the force nop logic.
>> That's slow (takes 61.4mS at 4mhz) though.
>
>
> Only to a computer... That is .0614 seconds, considerably less than
>a tenth of a second. Studies have shown that most people cannot even
>detect intervals of less than a tenth of a second. Methinks thou dost
>protest too much...
>
>
Gee I really didn't think that needed a smiley.
Allison
Date: Fri, 6 Apr 2007 20:20:24 -0700 (PDT)
From: Mr Ian Primus <ian_primus at yahoo.com>
Subject: Re: ST506 / ST412 - never see any 3 1/2"?
> >Any idea why? I'd love to have a handful of 20mb 3
> 1/2" drives to use
> >for various things but I never see them.
> >
> >I'm talking about drives from Rodime, Seagate,
> Lapine, etc... cerca 1985.
>
> Most were unreliable, Miniscribe comes to mind.
Hehe - Don't forget the wonderful Kalok Octa-gone...
Octa-went.
-Ian
----------------
Ah, yes, Kalok; a name that evokes many memories, none pleasant...
(although in my experience the Miniscribes weren't _too_ bad)
m
>
>Subject: Re: Hand-rolling a CP/M machine
> From: "Ethan Dicks" <ethan.dicks at gmail.com>
> Date: Tue, 24 Apr 2007 14:29:35 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On 4/24/07, Allison <ajp166 at bellatlantic.net> wrote:
>> One other thing.. CPUs..
>>
>> I've only mentioned Z80s.
>
>So far.
>
>> Others from the junkbox would be:
>>
>> 8080 (for the three voltage masochist).
>
>Indeed. But the last 8080 I saw in the field was in a 1970s B&W video game.
>
>> 8085 (Also makes for simple systems)
>
>Those are somewhat common if you hang around DEC equipment.
As I am.
>
>> NSC800 run it if you got one.
>
>Don't know that one - what makes it special?
National did a odd mix of z80 archetecture and 8085 interface.
It's a Z80 for the programmer and 8085 like for the hardware
hack.
>> Z180
>> Z280
>> ez80 (in Z80 mode)
>
>These all look like Z80 descendents to me - I'd probably rarely, if
>ever, run across one to harvest.
Z180s do end up in the stragest of places.
>> 8085s are common and makes a fair CP/M system. One caveat is that some
>> (far from all) applicaions software expects a Z80 though, most run on 8080
>> and above.
>
>Since the Z80 was rather prolific, and should still be easy to obtain,
>either from junked equipment or just new for a couple of bucks from a
>place like BG Micro, what would be the appeal of an 8085? Just a
>variant on the theme, or is there something neat about it that
>warrants investigation?
Z80s are easy to find/get as are 8085s.
>Since a bit of the requirements of such a system turn on the
>applications' needs more than the operating system's needs, I can
>throw into the mix that the things I'd probably most likely try to run
>would be some flavor of BASIC, Wordstar, an Infocom engine, and most
>likely a Scott Adams/Adventure International engine - pretty much the
>sort of stuff I would have run in the late 1970s through the mid-1980s
>if I'd had a CP/M system of my own. I'd say that a few hundred K of
>removable storage and a 64 or 80-char-wide screen should take care of
>all of those.
Infocom games are 80x24 for best results. For storage i'd advise at
least a 360k floppy (if you r doing floppy) as anything smaller is cramped.
CP/M programs and stuff bit larger (around 512k) storage systems easier.
the best example I give for that is:
Basic system, PIP ED,STAT, ASM, DDT, LOAD plus the CP/M BDOS assemble
and edit on one drive and between the .bak, Hex, OBJ, PRN you can easily
fill a 360k disk and then some.
So for storage (floppy) I always advise TEAC55F (or GFR strapped for 300rpm)
to get two side 80tracks and about 720/780k formatted. Or a 720K 3.5" floppy.
IDE disk makes the space issue go away as 8mb is a large drive for CP/M.
Allison
On 4/24/07, John A. Dundas III <dundas at caltech.edu> wrote:
>
> Henk,
>
> At 9:56 AM +0200 4/24/07, Gooijen, Henk wrote:
> > Hi,
> >
> >I feel like a fool ... I just can't get an RX01 drive
> >configured and attached in SIMH.
>
> As Joe mentioned, make sure only one device is using the CSR and
> vector in SIMH before booting RT-11. Then attach the device to the
> container file.
>
> >If I boot RT11 from a virtual RL02, and do .SH DEV,
> >the DX driver is listed as "Not installed".
>
> Right. It needs to be installed before you use it. For example,
>
> .INS DX:
>
> .LOAD DX:
>
> Now try .SHOW DEVICES and see what happens.
>
> John
>
IIRC you could give the RX02 a different CSR and Vector and tell the DY
driver the vector and csr at load time to get both in.
bill
--
d|i|g|i|t|a|l had it THEN. Don't you wish you could still buy it now!
pechter-at-gmail.com
--------------------Original Message:
Date: Tue, 24 Apr 2007 09:20:33 -0400
From: Allison <ajp166 at bellatlantic.net>
Subject: Re: Junkbox parts...
>
>Subject: Junkbox parts...
> From: M H Stein <dm561 at torfree.net>
> Date: Tue, 24 Apr 2007 03:41:05 -0300
> To: "'cctalk at classiccmp.org'" <cctalk at classiccmp.org>
>
>A couple of relevant sites:
>
>http://www.csd.uoc.gr/~hy325/spring-2006/docs/8042.pdf
>
>http://www.beyondlogic.org/keyboard/keybrd.htm
>
>mike
Thanks for the info. After years of using nicely encoded
keyboards the AT/PS2 deal is a mess.
Allison
---------------------------------- REPLY:
Well, you could always replace the encoder in the keyboard, although
I think the matrix has a few more lines than were used in the old days.
I've got a bunch of index-card-size SBC terminals (both colour and m/c)
that you could use as a kbd>RS232 encoder, but alas, they all use XT
type keyboards AFAIK.
There are of course commercial PS/2 or matrix<>RS232 encoders, but
the ones I use are a little expensive ($100, Hagstrom KE24).
Finally, here's more good info re reading a PS/2 keyboard:
http://www.computer-engineering.org/ps2keyboard/
mike
>
>Subject: Re: Hand-rolling a CP/M machine
> From: "Ethan Dicks" <ethan.dicks at gmail.com>
> Date: Tue, 24 Apr 2007 12:01:24 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On 4/24/07, Dave Dunfield <dave06a at dunfield.com> wrote:
>> > The point of ROM vs RAM at $0000 has been gone over a few times. Do
>> > "standard" CP/M machines use a shadow-ROM technique, or what, to
>> > cold-start?
>>
>> There are many ways to accomplish getting RAM at 0, even though the CPU
>> has to boot from there.
>
>I'm with you there.
>
>> Some systems force a JMP instruction onto the BUS during the first three
>> fetches, which transfers control to a ROM at a higher location.
>
>That seems like it would take a bit of extra circuitry to do.
Not bad at all, Three states and one is always 00h. Doesn't take much
to do that. The sequency you want is say "JMP FOOOH" or C3h, 00h, F0h
I think a pair of 74157s could encode that.
Another equally sneeky/sleezy trick was to force NOPs (00h) on the buss
till you hit the rom address where you disable the force nop logic.
That's slow (takes 61.4mS at 4mhz) though.
Allison
Allison
Hi,
I feel like a fool ... I just can't get an RX01 drive
configured and attached in SIMH.
If I boot RT11 from a virtual RL02, and do .SH DEV,
the DX driver is listed as "Not installed".
On SY: is DX.SYS and DXX.SYS, and since RT11 answered
to the command ".set rx0 locked"
"?KMON-F-File not found SY:RXX.SYS", I copied DXX.SYS
to RXX.SYS ... and reboot of course.
When I enter ".set rx0 locked" the response is now
"?KMON-F-Invalid set parameter".
I break to SIMH and enter "att rx0 simrx01.dat" and the
SIMH response is
RX: creating new file
RX: buffering file in memory
When I continue, and enter .SH DEV, DX is "Not installed".
The CSR for DX is in SIMH 177174, the default 177170 is
assigned to DY. I know that both drivers normally have the
same CSR, I don't see a problem here.
So, how do I attached and access (!) a virtual RX01 floppy?
Has anybody used RX01 in SIMH before?
thanks,
- Henk.
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>Subject: Re: Hand-rolling a CP/M machine
> From: "Ethan Dicks" <ethan.dicks at gmail.com>
> Date: Tue, 24 Apr 2007 12:01:24 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
One other thing.. CPUs..
I've only mentioned Z80s.
Others from the junkbox would be:
8080 (for the three voltage masochist).
8085 (Also makes for simple systems)
NSC800 run it if you got one.
Z180
Z280
ez80 (in Z80 mode)
8085s are common and makes a fair CP/M system. One caveat is that some
(far from all) applicaions software expects a Z80 though, most run on 8080
and above.
Allison
