18 May
2013
18 May
'13
1:02 p.m.
Hi, All,
I'm cleaning up some older stuff and I have a couple of external Mac
drives back from when I used to use them on a regular basis. I have a
400K M0130 shell (the drive died long ago and the external cable
disappeared after loaning it out nearly as long ago) and I have a few
of "beige" and "platinum" drives.
Right here and now, I have an M0131 in front of me. Google tells me
that it's 800K drive for Mac only (not Apple II), and that if I want
to use it with an old Mac, it has to be one with either the newer ROMs
(i.e., not a 128K or 512K) _or_ I have to run the ancient HD20 HFS
background task (which only works with the 512K, presumably due to
memory usage). I get why I'd need a ROM extension to use it to
read/write an HFS disk, but why would this drive not work with an
unexpanded 128K or 512K Mac as a single-sided 400K MFS drive? I know
Amigas have an "IDENT" feature so that the machine can wiggle some of
the control lines and get back if the drive is 3.5" or 5.25". Did
Apple do something like that?
Ultimately, I just want to have an external drive on the 128K Mac I
have sitting right here. I'd _love_ to have an original working M0130
but I don't need to buy one if I can use something already have here.
Does anyone know technical reasons why the M0131 is different from the
M0130 besides the different mech (slim-line 2 heads vs full-height 1
head)?
I have a memory that the external cable is different by one pin (head
select? head data?) but it's a fuzzy memory. Might it be possible to
"cut" the pin (via an adapter, not with clippers!) to make an 800K
drive appear and act like a 400K drive to a Original-ROM Mac?
Thanks for any input and pointers. All I've turned up is that they
are different and that the M0131 works with a 512K (with software) or
512Ke (new ROMs) natively.
If anyone happens to have cheap guts for an M0130, I have a shell I
wouldn't mine repopulating. The aluminum RF shield is also long gone,
but that can be approximated.
Thanks,
-ethan
18 May
18 May
1:48 p.m.
Does anyone know technical reasons why the M0131 is
different from the
M0130 besides the different mech (slim-line 2 heads vs full-height 1
head)?
I don't see why it would matter (and if anything, it's the 'wrong way
round for it to matter') but IIRC, the 800K drive sets the spindle speed
autmattically depending on which cylinder tis's on, the 400K drive takes
a PWM speed control signal from the Mac mainboard.
There are some oddiites in the floppy cabling, to the extnt that the
internal drive ribbon cables have 1 or 2 wires missign (solid plastic).
I think that a pin that's a power line (-5V?) on the logic board is
'remote eject' at the drive. But that couldn't be fixed with software, so
that can't be it.
Have tyou tried it? Given that it can be made to work on the Mac 512 with
software chages (new ROMs or an OS extension), I don;t think plugging it
in will do any damage.
-tony
19 May
19 May
1:14 a.m.
On Sat, May 18, 2013 at 4:48 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> Does anyone know technical reasons why the M0131
is different from the
> M0130 besides the different mech?
OK... modification to the question... does anyone know the specific
technical differences between versions of 800K Mac drives? It apparently
does matter.
http://68kmac.com/Mac128/Mac_128_Update/Entries/2007/9/1_Formatting_800K_MF…
IIRC, the 800K drive sets the spindle speed
autmattically depending on which cylinder tis's on, the 400K drive takes
a PWM speed control signal from the Mac mainboard.
I do remember that difference now that you mention it. The 400K
drives almost sang as they flew from track to track.
There are some oddiites in the floppy cabling, to the
extnt that the
internal drive ribbon cables have 1 or 2 wires missign (solid plastic).
I think that a pin that's a power line (-5V?) on the logic board is
'remote eject' at the drive. But that couldn't be fixed with software, so
that can't be it.
Found a reference... Pins "9 (-12v)" and "20 (speed)" for internal
cabling
(obviously there's no pin 20 on a 19 pin external connector).
Have tyou tried it? Given that it can be made to work
on the Mac 512 with
software chages (new ROMs or an OS extension), I don;t think plugging it
in will do any damage.
I doubt it will damage anything, but from what I've read, others have tried
it and it's known not to work. The "newer" 800K drives work but not the
older mech in the M0131
-ethan
11:01 a.m.
On Sat, May 18, 2013 at 4:48 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Alas I can't help you there. The only Apple 3.5" drive I've worked on is
the one in my Mac+. It's 800K (of course), and seems to be closely
related to a stnadard Sony half-height drive, the drive that HP used in
the 9114B, the 9153, the late version of the 9123, etc. It'c close enough
to that drive that I actyualyl receomend using old Apple drives as a
source of spares for fixing the HP machiens (nothing agains Apple, but
their drives are a lot easier to fidn than the HP ones).
I would be interested ot know what the differences in Apple drives are,
too. I wonder if it's basically the same drive with modifications to the
digital ASIC, or a totaly different unit.
> Does anyone know technical reasons why the
M0131 is different from the
> M0130 besides the different mech?
OK... modification to the question... does anyone know the specific
technical differences between versions of 800K Mac drives? It apparently
does matter.
http://68kmac.com/Mac128/Mac_128_Update/Entries/2007/9/1_Formatting_800K_MF…
The 800K drives are variable speed, but they set their own speed.
IIRC, the 800K drive sets the spindle speed
autmattically depending on which cylinder tis's on, the 400K drive takes
a PWM speed control signal from the Mac mainboard.
I do remember that difference now that you mention it. The 400K
drives almost sang as they flew from track to track. There are some oddiites in the floppy cabling, to
the extnt that the
internal drive ribbon cables have 1 or 2 wires missign (solid plastic).
I think that a pin that's a power line (-5V?) on the logic board is
'remote eject' at the drive. But that couldn't be fixed with software, so
that can't be it.
Found a reference... Pins "9 (-12v)" and "20 (speed)" for internal
cabling
(obviously there's no pin 20 on a 19 pin external connector). 
20 May
20 May
3:29 a.m.
On
Does anyone know technical reasons why the M0131 is
different from the
M0130 besides the different mech (slim-line 2 heads vs full-height 1
head)?
The big difference is that the
400k drive's motor speed is controlled by software in the mac driver
The pins were reused in 800k and later drives for other functions
I have a table somewhere which describes the exact cable changes and
the differences between the Mac and A][ versions of the drives. I'll try to
get over to storage later this week and dig it out.
9:42 a.m.
On Mon, May 20, 2013 at 6:29 AM, Al Kossow <aek at bitsavers.org> wrote:
Does anyone
know technical reasons why the M0131 is different from the
M0130...
The big difference is that the
400k drive's motor speed is controlled by software in the mac driver
The pins were reused in 800k and later drives for other functions From the descriptions of "yellow stripe" and
"red stripe" and a few
other nuggets I've dug up, I can see that Apple
did mess around
with pin definitions, but I've only managed to find one definition
so far, and as far as I can tell, it's for the 800K drives.
I have a table somewhere which describes the exact
cable changes and
the differences between the Mac and A][ versions of the drives. I'll try to
get over to storage later this week and dig it out.
That would be great. Thanks, Al!
At the moment, I think my best chance for swift progress is to stop
fiddling with the M0131 drives and go find my later "platinum" 3.5
drives (I used to use one with my Amiga 3000/A-Max combo). Those
appear to work with all Macs where the M0131 has the blind-spot with
the unupgraded Mac 128K/512K.
-ethan
5:18 p.m.
New subject: A rose by any other name
I just noticed that the cover of the January 1975 Popular Electronics
calls the Altair 8800 a "Minicomputer"!
How authoritative would we consider THEM for the definition?
--
Grumpy Ol' Fred cisin at xenosoft.com
6:17 p.m.
New subject: A rose by any other name
On 05/20/2013 05:18 PM, Fred Cisin wrote:
I just noticed that the cover of the January 1975
Popular Electronics
calls the Altair 8800 a "Minicomputer"!
How authoritative would we consider THEM for the definition?
In 1972, AES dubbed their cage-o-cards (the AES-80), a "microprocessor".
Terms of art have always been the territory of Humpty-Dumpty.
--Chuck
21 May
21 May
12:01 p.m.
New subject: A rose by any other name
On 05/20/2013 05:18 PM, Fred Cisin wrote:
DEC (certainly) and HP (I think) have been known to refer to a microcoded
control system (like half a DMC11) as a 'microprocessor'.
And of course HP refered ot the HP9830 as a 'calculator', for all it has
a full QWERTY keyboard and programs in BASIC.
-tony
I just noticed that the cover of the January 1975
Popular Electronics
calls the Altair 8800 a "Minicomputer"!
How authoritative would we consider THEM for the definition?
In 1972, AES dubbed their cage-o-cards (the AES-80), a "microprocessor".
20 May
20 May
6:39 p.m.
New subject: A rose by any other name
On Mon, May 20, 2013 at 05:18:12PM -0700, Fred Cisin wrote:
I just noticed that the cover of the January 1975
Popular Electronics
calls the Altair 8800 a "Minicomputer"!
Didn't RadShack say (or at least strongly imply) the same thing about the
TRS-80 Model II? And I'm sure I've seen S-100 card cages called
"mainframes".
John
21 May
21 May
7:45 a.m.
New subject: A rose by any other name
I had also seen references to the Apple Lisa as a minicomputer. In looking
up the definition, it states "a computer between a mainframe and
microcomputer". That's not too helpful. It is completely relative to what
you, as the reader, thinks a micro and mainframe and is also related to the
time frame of the comparison. For the time, the Lisa could be a
minicomputer.
On Mon, May 20, 2013 at 9:39 PM, John Wilson <wilson at dbit.com> wrote:
On Mon, May 20, 2013 at 05:18:12PM -0700, Fred Cisin
wrote:
I just noticed that the cover of the January 1975
Popular Electronics
calls the Altair 8800 a "Minicomputer"!
Didn't RadShack say (or at least strongly imply) the same thing about the
TRS-80 Model II? And I'm sure I've seen S-100 card cages called
"mainframes".
John
22 May
22 May
4:03 p.m.
New subject: A rose by any other name
Date: Mon, 20 May 2013 17:18:12 -0700 (PDT)
From: Fred Cisin <cisin at xenosoft.com>
I just noticed that the cover of the January 1975 Popular Electronics
calls the Altair 8800 a "Minicomputer"!
How authoritative would we consider THEM for the definition?
I was just at the Living Computer Museum in Seattle, I saw a PDP-8, an
Altair and an Imsai, and I couldn't help thinking how much alike they looked.
And since the Altair is in the running for the title of the first
commercial Microcomputer, it's not surprising someone would have used
an older term to describe it.
Phil
11:27 p.m.
New subject: A rose by any other name
On 05/22/2013 04:03 PM, Phil Budne wrote:
I was just at the Living Computer Museum in Seattle, I
saw a PDP-8, an
Altair and an Imsai, and I couldn't help thinking how much alike they looked.
And since the Altair is in the running for the title of the first
commercial Microcomputer, it's not surprising someone would have used
an older term to describe it.
"Microcomputer" was an evolutionary term. Remember that, in 1973, you
had both multi-chip CPUs (e.g. National IMP-16 set) in addition to the
single-chip (e.g. 8008) CPUs, although calling an 8008 a single-chip CPU
might still be considered by some to be a stretch, given the amount of
support logic required. So, while a single-chip CPU was considered to
be evolutionary back then, the significance was mostly recognized by the
technical types in the IC business.
I seem to recall that in 1969-70, the SN74181 was viewed as a major step
forward and the speculation began about putting a whole CPU on a chip.
I remember conveying the excitement to some friends in the business who
didn't see the significance of a single-chip CPU, particularly given the
speed of MOS logic back then--a whole bipolar CPU on a chip was viewed
as a more remote target, owing to fabrication and power issues. MOS had
the edge for rather complex circuits, especially for things such as
shift registers and whatnot.
At least that's what I remember. What *was* the first bipolar CPU on a
chip--would that have been the SMS-300? I'd probably call it more of a
microcontroller, but maybe that's splitting hairs. TI had their I2L
version of the TMS9900, but that was somewhat later.
--Chuck
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aek＠bitsavers.org -
ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
cisin＠xenosoft.com -
ethan.dicks＠gmail.com -
phil＠ultimate.com -
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wilson＠dbit.com