4 Feb
2007
4 Feb
'07
12:05 a.m.
--- Tony Duell wrote wrote:
I see nothing wrong with that. The Tandy machines
seemed like decent computers for the money. I wouldn't
mind picking up a TRS-80 someday.
Interesting.
Most people seem to say nice things
about
the Apple ]['s design. I'd love to hear
some
informed
bashing ;) . Could you elaborate some about the
machine's short comings from your perspective?
Firstly let me emphasise that my first computer was
a
TRS-80 Model 1. And
I thus do have a soft spot for that machine.
Irrational, probably, but
there you are. I've got several TRS-80s now (M1, M3,
M4, CoCo, M100) and
all have proved _very_ reliable. Odd considering
other
people's
expieneces, but I must have replaced perhaps a dozen
components _total_
in all said machines. Now, the Apple ][...
I had a lot of rpboelsm with it randomly crashing.
In
the end I took the
whole thing apart and stuck an ammeter in the 5V
output of the power
supply. It turend out that the mainboard (48K RAM) +
languge caed + 1
floppy drive drew _more_ than the rated current of
the
supply as given in
the techincal manual If you added more drives, a
serial card, etc, it
became ridiculous.
Strange, I haven't noticed any stability problems with
my ][ and ][+ under similar loads. Still, an unstable
machine is unlikely to impress.
Much has been said about the Apple ][ disk
controlle,
and how it's a
clever design. Well, a minimal-component design
certainly, but I didn't
like it. Not having a track0 sensor seemed like a
Bad
thing for starters
(continually banging the head against the stop does
not improve the
alignemnt!). The drives are Shugart mechanisms with
the IMHO poor
plastic-cam-with-a-spiral-groove head positioner,
and
becuase the drives
are non-standard you can't use any others (unlike
the
TRS-80 where you
can use any 5.25", 3.5" or 3" drives). But for me
the
biggest problem was
that the Apple couldn't read/write disks from other
machines, unlike the
TRS-80, which used a WD1771 controller and could
handle any single-desity
5.25" disk (I spent many late nights getting it to
read the disks from
the school's RML380Z computers, which also used 1771
controllers).
What can I say? The Disk II, either you love it or you
hate it. :)
To be fair though, the Apple Disk II system was not
the only game in town. While they weren't common, you
could get a 3rd party 8" MFM floppy system if you
wanted to.
Would you recoil in horror if I told you that some
companies made single sided 40 track 3" (Amdisk) and
double sided 80 track 5.25" (Rana Elite 3) drives for
use with the original Disk II controller? ;)
I didn't like the Apple ][ I/O system. Memory
space
was tight, but they
wasted lots of space with those 'soft switches' and
single-bit inputs. It
could all have been packed into a few bytes. I am
pretty sure the 6821 if
not the 6522 was available when the Apple ][ was
designed.
Fair enough.
The first seiral port for the Apple ][ was a
bit-banger. It was the only
one I had for some time, and it was almost unusable.
The TRS-80 used a
real UART, and worked. Yes, there were better serial
ports avaiable for
the Apple later.
Was this an early serial board or were you using the
game port? I've always enjoyed the luxury of a 6551
equiped board (Super Serial Card II).
I think Woz was allergic to peripheral chips in the
beginning. :)
The Apple text display did have lower case (wich the
TRS-80 didn't as
standard), but you couldn't mix text and graphics on
the same part of the
screen. Apple gave you the high-res mode, but
working
out the addresses
gave me headaches (all to save a few chips IMHO!).
And
colours in the
high-res mode were essentially obtained as NTSC
artefacts.
The TRS-80 graphic characters are pretty neat. The
stock Apple character generator was certainly poor in
terms of graphics characters. Heck, it didn't have
lower case characters! Needless to say, soft hires
character generators were a pretty common project. It
would have been nice to have had one in the firmware.
The hires mode is somewhat byzantine and it was indeed
that way to save chips! :) Fortunately, it's not too
bad to work with if you use a lookup table to untangle
the memory map. I have no doubt it has turned off
plenty of people though.
The colors are NTSC artifacts! :) I thought that was a
neat hack. How did they deal with that in PAL land?
And another oddiity. The whole design of the Apple
][
seems to have been
to save a chip if at all possible (provided the
machine still works --
just).
Bingo! Legend has it that Woz's aesthetic ideal was to
bum a design down to as few chips as possible. Almost
a Madman Muntz I suppose.
Methinks you're not a fan of Clive Sinclair either? :)
And yet the kayboard was encoded in hardware.
Why? It meant you
couldn't implelement a lower case keyboard in
software
(there are the
well-known shift key mods where you run a wire from
the shift keyswitch
to one of the single-bit inputs on the games
connector, which shouldn't
have been necessary).
This is a good point. My guess would be that Woz
designed the Apple II as just a naked board, kind of
like the Apple I. Apple sold you the motherboard and
it was up to you to find a power supply , keyboard,
and housing. Apple did offer the ][ that way early on.
Of course I like elegant, simple designs (the HP9100
is a case in point).
But the Apple ][ seems to have been a case of
cutting
too many corners.
And I had a lot of problems as a reuslt.
-tony
Thanks for your input Tony. While I've never had
reliability problems with my ][/ ][+ I think I
understand where you're coming from. I like the Apple
because I feel it's a machine with interesting
capabilities yet made from a small amount of simple
parts. It's a machine I can both grasp and enjoy.
What's your opinion of the BBC Micro? I've never had
the pleasure of using one, but on paper it sounds a
lot like a fast Apple II with a pair of 6522, 6845,
hardware ACIA, 1770 FDC, and enhanced basic.
Liam Busey
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4 Feb
4 Feb
2:03 p.m.
I see nothing wrong with that. The Tandy machines
seemed like decent computers for the money. I wouldn't
mind picking up a TRS-80 someday.
If you don't want 'the first', try to get a Model 4, original
(non-gate-array) CPU board versions. It's got a couple of features not
found on the earlier machines, including an 80*24 text mode display and
selectable memory mapping allowing RAM at location 0 so you can run
normal CP/M as well as TRS-DOS, LDOS, etc. And the origianl CPU board is
all standard chips with some PALs dotted about,
Strange, I haven't noticed any stability problems
with
my ][ and ][+ under similar loads. Still, an unstable
machine is unlikely to impress.
i must admit my comments are based on one machine, and are hardly
scientific. Perhaps my machine had chips that drew more current than
average, or someting (still, a good design would haev taken the
worst-case figures).
[...]
Would you recoil in horror if I told you that some
companies made single sided 40 track 3" (Amdisk) and
double sided 80 track 5.25" (Rana Elite 3) drives for
use with the original Disk II controller? ;)
Yes, I remember seeing those advertised in Byte. Still, they came out a
good few years after the Apple drive, and even then the choice of drives
as limited compared to, say, the TRS-80.
The first
seiral port for the Apple ][ was a
bit-banger. It was the only
one I had for some time, and it was almost unusable.
The TRS-80 used a
real UART, and worked. Yes, there were better serial
ports avaiable for
the Apple later.
Was this an early serial board or were you using the game port? I've always enjoyed the luxury of a
6551
equiped board (Super Serial Card II).
I've also seen 6850-based serial cards for the Apple, but I don't think
they were Apple products (CCS or somebody).
I think Woz was allergic to peripheral chips in the
beginning. :)
Unlike Chuck Peddle who had a love of 6522s (the Sirius/Victor 9000 has 6
of thtm in it...)
The colors are NTSC artifacts! :) I thought that was a
neat hack. How did they deal with that in PAL land?
Well, there was the ;'Eurapple mod' which was a couple of cnt/blob
changes to the main PCB and a different master clock crystal. That got
you Europane video timing, albeit without PAL colour (most, if not all
Apples ][ machines sold over here came with that mod done). There was a
board you put in Slot 7 (which had soem extra timing signals brought out)
which did the appropriate phase-shifts to get PAL video. Or there were
3rd party board to give RGB video.
Bingo! Legend has it that Woz's aesthetic ideal was to
bum a design down to as few chips as possible. Almost
a Madman Muntz I suppose.
Methinks you're not a fan of Clive Sinclair either? :)
How ever did you guess :-). No I don't much care for his kludges. Suffice
it to say that I once did battle with a QL (which at the time sold for
\pounds 400). My comments were that had it sold for \pounds 600 but had
working serial ports, a real keyboard, and a disk drive, then I might
have actually bought one.
understand where you're coming from. I like the
Apple
because I feel it's a machine with interesting
capabilities yet made from a small amount of simple
parts. It's a machine I can both grasp and enjoy.
I am suprised by that last comment. Actually some parts of the Apple
hardware are quite difficult to understnad properly becuase they do use
unobvious tricks to save components. It reminds me of some of the
circuits you find in those Radio Shack '300 in 1' kits. Some of those are
not easy to follow IMHO.
In may ways a somewhat more complicated computer can be easier to
understand because everything is done in the obvious way without trying
to save every last gate.
What's your opinion of the BBC Micro? I've never had
the pleasure of using one, but on paper it sounds a
lot like a fast Apple II with a pair of 6522, 6845,
hardware ACIA, 1770 FDC, and enhanced basic.
I'd rather have an ACW :-) (This is a joke which I'll explain in a moment)
The BBC micro is IMHO,. the best 6502-based home computer ever, it's one
of the best of the 8-bitters (no matter what processor). The only thing
the Apple has that the Beeb doesn't are the expansion slots. But a Beeb
has a printer port, disk controller (8271 on early machines, 1770 on
later models),serial port (The ACIA is also used for the cassette
interface, BTW), ADC, user port, expansion bus, etc. And the BASIC is
excellent. Named procedures with formal parammeters and local variables,
multi-line functions, built-in assembler, etc, etc, etc. And there are
bank-switched ROM sockets where you can put other language ROMs (or
applications, or...)
Now for the omment on the ACW. An ACW is an Acron Cambridge Workstation.
Take a BBC B+ (64KL RAM) board. Put it in a case with a colour monitor,
floppy drive and hard drive. Now add a coprocessor board containing a
32016 and 4M RAM (!). As a workstation it's let down by the BBC's
graphics (excellent for a home computer, but not up to workstation
standards). But as a 'home micro' it does everything the Beeb does and a
lot more.
-tony
3:57 p.m.
On 2/4/07, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
If you don't want 'the first', try to get
a Model 4, original
(non-gate-array) CPU board versions. It's got a couple of features not
found on the earlier machines, including an 80*24 text mode display and
selectable memory mapping allowing RAM at location 0 so you can run
normal CP/M as well as TRS-DOS, LDOS, etc.
Ooh... didn't know that the M4 could run CP/M. When I was in High
School, our "Computer Math" class was done with a M3 and M4 running
TRS-DOS. If I'd known I could have gotten CP/M for it at the time (c.
1983), I would have been happy to bring that in. I was on independent
study anyway.
I'll have to see what I have lurking around in the way of TRS-80
hardware now. I got some right before I left for the Pole and it was
put away in my absence, so I'm not even sure what it all is (beyond a
Model 3 that did not come up during an initial check-out).
-ethan
4:40 p.m.
On 2/4/07, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
There was a CP/M+ for it (the M4 could officially take 128K of RAM, I
believe there were hacks to put 256K chips, not 64K in bank 1...).
Mind you, I am not sure why you'd _want_ to run CP/M on it. The 'native'
TRS-DOS 6.x (aka LS-ODS) is a much nicer OS, with loadable device
drivers, some (limited) I/O redirection, a better scripting facility, etc.
If you don't want 'the first', try to
get a Model 4, original
(non-gate-array) CPU board versions. It's got a couple of features not
found on the earlier machines, including an 80*24 text mode display and
selectable memory mapping allowing RAM at location 0 so you can run
normal CP/M as well as TRS-DOS, LDOS, etc.
Ooh... didn't know that the M4 could run CP/M. When I was in High School, our "Computer Math" class was done
with a M3 and M4 running
TRS-DOS. If I'd known I could have gotten CP/M for it at the time (c.
The Model 4 will run all Model 3 software, including booting all Model 3
OSes. If you were running Model 3 TRS-DOS (TRS-DOS 1.x) I can understand
why you'd want to run something else :-)
-tony
8:23 p.m.
On 2/4/07, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Yep... we all got one disk which worked on either machine. I can't
recall the exact version, but 1.something sure sounds familiar.
-ethan
There was a CP/M+ for it (the M4 could officially take
128K of RAM, I
believe there were hacks to put 256K chips, not 64K in bank 1...).
Interesting. So much I didn't know about the machines at the time (I
was programming the C-64 for money at the time, so that took up all my
attention).
Mind you, I am not sure why you'd _want_ to run
CP/M on it. The 'native'
TRS-DOS 6.x (aka LS-ODS) is a much nicer OS, with loadable device
drivers, some (limited) I/O redirection, a better scripting facility, etc.
Because in High School, I couldn't afford a machine that ran CP/M, but
I got a chance to use them on occasion. It would have been nice to
get some experience on a platform that was in widespread use at the
time (although its market share was already shrinking due to the
recent release of PC-DOS :-P)
School, our
"Computer Math" class was done with a M3 and M4 running
TRS-DOS. If I'd known I could have gotten CP/M for it at the time (c.
The Model 4 will run all Model 3 software, including booting all Model 3
OSes. If you were running Model 3 TRS-DOS (TRS-DOS 1.x) I can understand
why you'd want to run something else :-)
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