27 May
2006
27 May
'06
9:11 a.m.
Some of which are vintage:
http://tinyurl.com/k76mv
It's a shame that Bob won't run on a PC Jr...
Cheers,
Chuck
27 May
27 May
9:18 a.m.
Chuck Guzis wrote:
Some of which are vintage:
http://tinyurl.com/k76mv
It's a shame that Bob won't run on a PC Jr...
Cheers,
Chuck
The PCjr, in a grainy synthesised voice says 'Byte me'
http://www.brutman.com/PCjr
5:50 p.m.
Michael B. Brutman wrote:
The PCjr, in a grainy synthesised voice says 'Byte
me'
(which is quite a trick considering that byte isn't one of the
preprogrammed phonetics :-)
--
Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/
Help our electronic games project: http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
A child borne of the home computer wars: http://trixter.wordpress.com/
28 May
28 May
6:54 p.m.
Chuck Guzis wrote:
Some of which are vintage:
http://tinyurl.com/k76mv
It's a shame that Bob won't run on a PC Jr...
I got a bit annoyed by the "We appreciate the fact that there's an alternative
to Windows Media Player; we just wish it were a better one." ending to the
Realplayer write-up though: there have been lots of perfectly good (and often
free) alternatives to windows media player for a *long* time. Talk about
sloppy journalism!
cheers
J.
20 Jun
20 Jun
3:54 p.m.
--- Chuck Guzis <cclist at sydex.com> wrote:
Some of which are vintage:
http://tinyurl.com/k76mv
It's a shame that Bob won't run on a PC Jr...
Cheers,
Chuck
LOL LOL LOL. Friggin peanut. LOL LOL
What, and the Tandy 2000 don't figure anywhere on that
list? I guess they're talking about the worst well
known disasters. Those accompanied by a media blitz.
Pity the poor *less known* disaster who's company
didn't have the capitol IBM had. They don't get
mentioned. Nuh uh :(
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21 Jun
21 Jun
9:02 a.m.
On 6/20/2006 at 3:54 PM Chris M wrote:
What, and the Tandy 2000 don't figure anywhere on
that
list? I guess they're talking about the worst well
known disasters. Those accompanied by a media blitz.
Pity the poor *less known* disaster who's company
didn't have the capitol IBM had. They don't get
mentioned. Nuh uh :(
Has anyone ever compiled a list of IBM PC and PC/XT compatibles for
historical purposes (outisde of the no-name Taiwanese clones, that is)?
For example, I recall that ETA made use of the Stearns PC; the big
attraction being that the Stearns used an 8086--and was made in Minnesota.
Cheers,
Chuck
4:19 p.m.
What, and the Tandy 2000 don't figure anywhere on
that
list? I guess they're talking about the worst well
From what I've heard, the Tandy 2000 wasn't a
bad machine. It wasn't IBM
PC compatible, which made it a commercial flop, but
technically there
wasn't that much wrong with it.
But the PCjr wasn't techically a good machine. It also wasn't truely PC
compatible. I can think of little to recomend it, actually ;-)
-tony
5:31 p.m.
Tony Duell wrote:
But the PCjr wasn't techically a good machine. It
also wasn't truely PC
compatible. I can think of little to recomend it, actually ;-)
As a PC compatible, the PCjr isn't too bad. As a PC clone, it is awful.
Pros
- Significantly less expensive than a PC.
- Many extra cost items built in (serial, game interface, CGA, etc.)
- Fairly compatible software wise.
- Small footprint.
- Diagnostics built in.
- CGA+ graphics (640x200x4 and 320x200x16)
- Much more advanced sound than a PC
Cons
- Expansion capability.
- Some hardware in non-standard places, which broke some software.
- Shared memory between video and main memory, which slowed things down.
- Non-standard connectors for joysticks, monitors, etc.
I like the machine a lot. Getting it to do 'PC' type things (like
adding a hard drive) is a major challenge and requires some thought and
work.
Mike
5:45 p.m.
On 6/21/2006 at 7:31 PM Michael B. Brutman wrote:
- Expansion capability.
- Some hardware in non-standard places, which broke some software.
- Shared memory between video and main memory, which slowed things down.
- Non-standard connectors for joysticks, monitors, etc.
I like the machine a lot. Getting it to do 'PC' type things (like
adding a hard drive) is a major challenge and requires some thought and
work.
IIRC, the Peanut also has no DMA controller and a rather miserly PSU. In
comparison to the "clone XTs", it was actually pretty expensive for what it
offered. It could be that IBM never fully anticipated the stiff
competition from the Asian clone builders.
Cheers,
Chuck
6:25 p.m.
Chuck Guzis wrote:
IIRC, the Peanut also has no DMA controller and a
rather miserly PSU. In
comparison to the "clone XTs", it was actually pretty expensive for what it
offered. It could be that IBM never fully anticipated the stiff
competition from the Asian clone builders.
I forgot the lack of DMA, but it is more of a nuisance than a serious
design flaw. When using an OS like DOS the lack of DMA just made disk
access a little slower, as DMA could move memory to and from the floppy
disk faster than a processor loop could.
A bigger shortcoming that I should have mentioned was having the
keyboard using the NMI interrupt instead of IRQ1. I forget the exact
reason for this, but it resulted in a lot of lost keystrokes an annoying
beeps.
The original power supply was 33 watts, which was enough for a 128K
single floppy system with maybe a sidecar or two. The power supply was
later upgraded to 45 watts. And of course, to power the ridiculous
sidecars there was a power supply sidecar as well.
IBM never considered other things as competition back then .. Compared
to the 64 or other 'home machines', it was very expensive, but also very
capable. Compared to the PC, it was inexpensive and 'good enough'.
Compared to cheap PC or XT clones, it was a hard sell.
7:47 p.m.
On 6/21/2006 at 8:25 PM Michael B. Brutman wrote:
A bigger shortcoming that I should have mentioned was
having the
keyboard using the NMI interrupt instead of IRQ1. I forget the exact
reason for this, but it resulted in a lot of lost keystrokes an annoying
beeps.
Reason? So the Peanut user could mess up his modem and floppy transfers by
banging on the keyboard at the wrong time? Maybe to make sure that no one
would try to hack in an 8087 NDP?
I wonder if it was because the chicklet keybard had no internal buffering,
so NMI was thought to make it possible to grab keys as soon as they were
hit.
Cheers,
Chuck
9:40 p.m.
Chuck Guzis wrote:
Reason? So the Peanut user could mess up his modem
and floppy transfers by
banging on the keyboard at the wrong time? Maybe to make sure that no one
would try to hack in an 8087 NDP?
I wonder if it was because the chicklet keybard had no internal buffering,
so NMI was thought to make it possible to grab keys as soon as they were
hit.
Cheers,
Chuck
The keyboard (chicklet or otherwise) does not buffer keystrokes, so the
8088 has to pull them as fast as they come. The non-maskable interrupt
is used to do the deserialization, which is what causes the mess with
the other I/O.
With the serial port sending data at 2400 bps the 8088 was fast enough
to service the keyboard without dropping characters. Above 2400 bps if
you used the keyboard you might lose something.
As for the diskette drive, I can't remember what the trick was, but the
machine had a way to disconnect the keyboard from the NMI while the
diskette was being serviced.
22 Jun
22 Jun
4:06 p.m.
A bigger shortcoming that I should have mentioned was
having the
keyboard using the NMI interrupt instead of IRQ1. I forget the exact
reason for this, but it resulted in a lot of lost keystrokes an annoying
beeps.
There was a reasonable reason for this.
The PC keyboard is farily hardware-intensive. The keyboard sends a serial
data stream that goes into a shfit register on the PC mainboard. When a
character has been received (IIRC), ther hardware generates an IRQ1 and
holds the keyboard clock line, preventing the keyboard from sending
another character until the first one has been read by the 8088
The PCjr keyboard is software-intensive. Whether you use the IR link or
the cable, the serial data stream is decoded by the 8088, there is no
shift register on the PCjr mainboard. Also, in the PCjr, there's no way
to tell the keyboard to stop sending because the main processor hasn't
read the character yet.
Therefore in the PCjr, you need a high-priorty interrupt (i.e, NMI) which
is generated when the keyboard sends a bit, The 8088 takes over then,
reads in the character from the keyboard and processes it. Otherwise
you'd loose or mangle an awful lot of keypresses.
-tony
23 Jun
23 Jun
7:18 p.m.
Your intimate knowledge the machine machine betrays a deep, but
forbidden love for it. ;-)
Tony Duell wrote:
A bigger
shortcoming that I should have mentioned was having the
keyboard using the NMI interrupt instead of IRQ1. I forget the exact
reason for this, but it resulted in a lot of lost keystrokes an annoying
beeps.
There was a reasonable reason for this.
The PC keyboard is farily hardware-intensive. The keyboard sends a serial
data stream that goes into a shfit register on the PC mainboard. When a
character has been received (IIRC), ther hardware generates an IRQ1 and
holds the keyboard clock line, preventing the keyboard from sending
another character until the first one has been read by the 8088
The PCjr keyboard is software-intensive. Whether you use the IR link or
the cable, the serial data stream is decoded by the 8088, there is no
shift register on the PCjr mainboard. Also, in the PCjr, there's no way
to tell the keyboard to stop sending because the main processor hasn't
read the character yet.
Therefore in the PCjr, you need a high-priorty interrupt (i.e, NMI) which
is generated when the keyboard sends a bit, The 8088 takes over then,
reads in the character from the keyboard and processes it. Otherwise
you'd loose or mangle an awful lot of keypresses.
-tony
24 Jun
24 Jun
1:50 p.m.
3:51 p.m.
Tony Duell wrote:
[PCjr]
Tony, I'm worried that you are actually constructed from easy to replace
individual TTL components. The 'deep, forbidden' love comment was
supposed to be a very, very funny joke along the lines of a romance novel.
Oh well. You came out of the closet at least. ;-)
Mike
Your intimate knowledge the machine machine
betrays a deep, but
forbidden love for it. ;-)
Oh, I'll admit to owning a PCjr (with the 128K expansion card, one 5.25"
drive, and a parallel port sidecar), and to buying the techref.
I've read the latter of course, and some of the information has stuck in
my brain.
But as regards 'loving it', well, I can safely say it's not one of my
favourite machines...
-tony
26 Jun
26 Jun
4:05 p.m.
[PCjr]
But as regards 'loving it', well, I can safely
say
it's not one of my
favourite machines...
-tony
I often tire of the massive # of units I'm compelled
to keep around. I don't use them for much (don't use
them at all lately). I long for a situation where I
could hold onto say 1 or 2 (or 6?) classic machines. I
don't see that day dawning anytime real soon though.
But some pick 1 or a few puters, evidently due to some
deep seated neuroses in all likelihood LOL LOL. The
Peanut is as *suitable* for this approach then
anything out there I'd have to say.
I do have to admit that once I did crack the hood on
my old beat up Peanut and saw THOSE CHIPS...I groaned
inwardly. I then purposed to collect only machines for
which all parts were *commonly* available. Then I
found a *new* 2000. Then the Mindsets. Don't even know
what's inside my Canon Cat. And the one thing the Jr
has going for it is that enough of them were made to
make parts replacement something less of a chore. For
now anyway...
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5:33 p.m.
I do have to admit that once I did crack the hood on
my old beat up Peanut and saw THOSE CHIPS...I groaned
AFAIK, the only really custom part in the PCjr is the video gate array.
There's a couple (?) of ROMs of course, but the rest of the stuff is
standard.
inwardly. I then purposed to collect only machines
for
which all parts were *commonly* available. Then I
I tried to make that decision too. I avoided the early 80's home
computers, with their ULAs, etc.
And then the problems started. I had to have a BBC micro, right? Even
though there are a pair of ULAs in it. And that led to be wanting, and
eventually getting an ACW....
And I fell in love with HP machines, particularly desktop 'calculators'.
The early ones -- 9100, 98x0, etc were OK. Just transistors, and then TTL
and simple PROMs. The 9815 was a 6800 system, and I could fix that (apart
from the thermal printhead hybrid). But the 9825, 9845
had custom hybrid
processor modules, the 80 series are all custom chips, and so on.
I
reluctantly added them to the collection... The HP9000/200 series are OK
(68000 + TTL + PALs + not too much else), the 9000/300s seem to have big
ASICs in them next to the processor.
Oh well... My justification is that they're beautiful machines, and if
they fail there's always a chance I'll find another one with a different
fault. Might as well enjoy them now -- but not depend on them.
found a *new* 2000. Then the Mindsets. Don't even
know
what's inside my Canon Cat. And the one thing the Jr
That worries me. How can you own a machine for more than an hour without
cracking the case and seeing what all the chips are?
-tony
22 Jun
22 Jun
1:46 p.m.
Michael B. Brutman wrote:
I like the machine a lot.
Me too. It got some things very right (wireless keyboard means you can
compute on the living room couch, built-in graphics and sound, small and
light = portable, built-in user-accessible diagnostics) and some things
very wrong (expandability being the most notable offender). I will
always have a soft spot in my heart for it.
--
Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/
Help our electronic games project: http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
A child borne of the home computer wars: http://trixter.wordpress.com/
3:57 p.m.
Tony Duell wrote:
[...]
But the PCjr wasn't techically a good
machine. It also wasn't truely PC
compatible. I can think of little to recomend it, actually ;-)
As a PC compatible, the PCjr isn't too bad. As a PC clone, it is awful.
Cons
- Expansion capability.
- Some hardware in non-standard places, which broke some software.
- Shared memory between video and main memory, which slowed things down.
- Non-standard connectors for joysticks, monitors, etc.
No DMA controller!
A nasty custom gate array chip for the video circuitry
That darn chicklet infra-red keyboard
-tony
21 Jun
21 Jun
5:39 p.m.
--- Tony Duell <ard at p850ug1.demon.co.uk> wrote:
The Tandy 2000 was a neat machine in it's own right,
but there were 40+ tech center mod bulletins. Could
involved soldering jumpers, cutting traces, etc.
Supposedly once Xenix got ported, all these little
quirks started popping up. There's probably alot more
info then I can give on the comp.sys.tandy newsgroup.
Also google "Jeff Hellige" for the Tandy 2000 FAQ
file.
There's also the weird crt controller by SMC (and
floppy data seperator). Where are you supposed to find
replacements for those???
The Peanut was an interesting machine in it's own
right. It certainly had it's deficiencies, the floppy
drive, weird upgrade path. But early IBMers in general
had problem drives and whatnot. Yet if you look under
the hood there was some interesting stuph going on.
Like how they used a gate array to make the video
memory appear as if it was in the b800:0000 area, when
in reality it was physically located down low in
memory (anyone know if the Tandy 1000 did the same
thing?). As far as compatibility, as long as you could
plug a 2nd floppy drive in (aftermarket or home
brewed) you were mostly compatible as I understand.
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From what
I've heard, the Tandy 2000 wasn't a bad
machine. It wasn't IBM
PC compatible, which made it a commercial flop, but
technically there
wasn't that much wrong with it.
But the PCjr wasn't techically a good machine. It
also wasn't truely PC
compatible. I can think of little to recomend it,
actually ;-)
-tony
22 Jun
22 Jun
4 p.m.
The Tandy 2000 was a neat machine in it's own
right,
[...]
There's also the weird crt controller by SMC
(and
floppy data seperator). Where are you supposed to find
replacements for those???
Presumably from the same place that you get a replacement video gate
arrayor a keyboard microcontroller from for the PCjr....
-tony
4:32 p.m.
--- Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Right mate, go ahead, rub salt in the wounds!
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The Tandy
2000 was a neat machine in it's own
right,
[...]
There's also the weird crt controller by SMC
(and
floppy data seperator). Where are you supposed to
find
replacements for those???
Presumably from the same place that you get a
replacement video gate
arrayor a keyboard microcontroller from for the
PCjr....
23 Jun
23 Jun
3:24 p.m.
There's also the weird crt controller by SMC
(and
floppy data seperator). Where are you supposed to
find
replacements for those???
Presumably from the same place that you get a
replacement video gate
arrayor a keyboard microcontroller from for the
PCjr....
6520
days inactive
6551
days old
24 comments
6 participants
participants (6)
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
chrism3667＠yahoo.com -
julesrichardsonuk＠yahoo.co.uk -
mbbrutman-cctalk＠brutman.com -
trixter＠oldskool.org