Re: IIe, IIgs, Mac LC-II hardware compatibility questions.

[dempson@actrix.gen.nz (David Empson)]

Dennis Jenkins <dennis@usb.com> wrote:

>       I have a beige Apple IIe, unenhanced.  It has a beige 5.25" floppy
> drive.  I recently acquired a "Woz limited edition" Apple IIgs (whatever
> that means).  It has a platinum 5.25" floppy drive.
> 
> 1) Can I place both floppy drives on the same system, daisy chained
> together?  I want to copy files from one disk to another and want to
> avoid switching floppies like mad.

Assuming the drives are both of the "UniDisk" type (either UniDisk 5.25
or Apple 5.25 Drive) with a D-19 connector, you can daisy-chain them and
use them both on the IIgs.  They will also work on the IIe if you have
the UniDisk 5.25 controller with the D-19 connector.

(If the so-called "beige" drive is actually a Disk ][, with a black
front panel and ribbon cable connecting to the computer, then you need
an adaptor to connect it to D-19; a corresponding adaptor allows a
UniDisk 5.25 or Apple 5.25 Drive to be connected to a Disk ][
controller.)

> 2) How much does a 3.5" floppy drive for the IIgs usually go for?

No idea.  The Apple 3.5 Drive is relatively common, so it should be easy
to get hold of.  The UniDisk 3.5 and SuperDrive are rarer (and the
controller card required for the SuperDrive is as rare as hens' teeth).

> Can the 3.5" be hooked up to the IIe.

With difficulty.  The 5.25" controller cards do not support a 3.5"
drive.

There are two parts to the equation: drive model and disk controller.


There are three 3.5" drive models made by Apple which work on various
Apple II models:

1. The UniDisk 3.5.  This is a white drive, the same colour as the IIc.
It has a thin eject button above the line of the disk insertion cutout,
and a pinhole for manual eject in line with the disk insertion cutout.
It has a red activity light.

2. The Apple 3.5 Drive.  This is a platinum drive, the same colour as
the IIgs.  It has an eject button in line with the disk insertion
cutout, and the manual eject pinhole is through the middle of the
button.  It has a red or yellow activity light (early models are red,
late ones are yellow).

3. The SuperDrive.  This looks exactly the same as the Apple 3.5 Drive,
except I think the official ones all had a yellow activity light.  (It
is also known as "FDHD", for "Floppy Drive High Density".)

In addition to the above, Apple also made some Macintosh-only external
drives: 400K and 800K models.  These have no eject button.   These
drives will work on an Apple II with the right card, but are not as
convenient to use.

It is also worth mentioning the Applied Engineering 3.5" drive, which
looks very similar to the Apple 3.5 Drive, but has a bicolour LED
(read/write indication).  I know that they made a high density version
of this drive, which is unique in that it supports 1600K high density
disks on the IIgs, using the built-in controller.  I think they also
made 800K and SuperDrive-compatible drives.


Each of these drives should have a label on the underside which
indicates its model name.

There is a catch: the cases can be changed.  It is the mechanism inside
(and the interface board inside the case, between the drive mechanism
and the cable) which actually determine the behaviour of the drive.

The UniDisk 3.5, Apple 3.5 Drive and Macintosh 800K drive share the same
drive mechanism, but have different interface boards (none at all in the
case of the Mac 800K drive, if I remember right).  This is the same
drive mechanism used in the Mac Plus, Mac SE and Mac II.  These drives
all support 400K (single sided, double density) and 800K (double sided,
double density) formats.

The SuperDrive is the same drive mechanism used in the Mac IIx and later
models (until Apple switched to the "manual inject" type of drive, some
time around the introduction of the PowerMac), and in the FDHD upgrade
for the Mac II and SE.

The external SuperDrive has the same interface board as the Apple 3.5
Drive.  Its mechanism supports 400K and 800K disks, plus PC-compatible
MFM formats: 720K (double density) and 1440K (high density).  If this
drive is connected to a controller which only supports the Apple 3.5
Drive, then it will behave like one, i.e. it won't allow access to 720K
or 1440K disks.  You need a SuperDrive-aware controller to use MFM
disks.

In theory, you can cobble together your own drive by finding a case
(with appropriate interface board) and scavenging the mechanism from an
old Mac.


The UniDisk 3.5 is a "smart" drive.  Its interface board is actually a
small microcomputer, containing a 65C02 processor, RAM, ROM and an IWM
chip (the same disk controller used in the IIc, IIgs and early Mac
models).  The UniDisk 3.5 communicates with the host computer using a
packetised protocol called SmartPort: data is transferred between the
host computer and memory within the drive's computer, and is then
written to the disk (or vice versa for read).  This extra step (and the
slower transfer rate) makes the UniDisk 3.5 slower than the other
drives.

The other drives are all "dumb" in that the host computer controls the
drive mechanism directly.  They all require faster data transfer than
the UniDisk 3.5, which means that they need a faster host computer (or
special hardware support).


Now for the controller cards.  Apple made two:

"Apple 3.5 Floppy Disk Drive Interface Card".  This is nicknamed
"Liron", which is written on the back of the card.  This card work in a
IIe (and probably a II+) but not a IIgs.  It only supports the UniDisk
3.5.  This card is relatively common and quite cheap, since it is older
and has such limited capabilities.  (It was released in 1985.)

"Apple II 3.5 Disk Controller Card".  This is nicknamed "the SuperDrive
card", since it is the only card which fully supports the SuperDrive.
It also supports the Apple 3.5 Drive and UniDisk 3.5.  It doesn't
support 5.25" drives.  This card requires a IIgs or enhanced IIe.  It is
rare and relatively expensive.  (It was released around 1991 or 1992.)

There are two third-party controller cards that work with some of these
drives:

The "Universal Disk Controller" from Video Technology and Central Point
Software supports the Macintosh 400K and 800K drives and the Apple 3.5
Drive.  Some versions also support the UniDisk 3.5.  I don't know
whether it is safe to connect a SuperDrive to this card, but if it works
at all, it will only behave like an Apple 3.5 Drive.  This card will
also support 5.25" drives, but in a way which is not fully compatible
with older software.

Applied Engineering's "PC Transporter" is a PC/XT emulator card.  It
allows you to connect an Apple 3.5 Drive and can act as a controller for
it.  This isn't an ideal combination, because the drive operates very
slowly, cannot be booted and is incompatible with some software.


In addition to these controller cards, it is worth mentioning built-in
disk controllers:

The IIgs supports the Apple 3.5 Drive and the UniDisk 3.5 (and 5.25"
drives).  The Apple 3.5 Drive is the normal 3.5" drive for the IIgs.

The IIc+ has a built-in Apple 3.5 Drive, and also supports one external
Apple 3.5 Drive, as well as the UniDisk 3.5 and 5.25" drives.

The original firmware revision for the IIc only supports 5.25" drives
(the internal one plus one external drive).  The first revision to the
firmware added support for the UniDisk 3.5.


In all cases where you are mixing drive types on a daisy-chain
connector, they must be connected in the following order:

Apple 3.5 Drive or SuperDrive (maximum of two)
UniDisk 3.5
5.25" drives (maximum of two)

The theoretical limit for the UniDisk is 127 drives.  The practical
limit depends on the controller.  In general, you shouldn't connect more
than four drives in total to a single controller (six may be possible in
some cases).


Finally it might be worth mentioning the PC-compatible 3.5" drive
controllers.  The BlueDisk is the only one that comes to mind.  It uses
standard PC double density and high density drives, but only support MFM
720K and 1440K disk formats, so it won't be compatible with standard
Apple II 3.5" disks (800K).

> 3) Can a Mac LC-II use the same mouse/keyboard as the IIgs?

Yes.

Some third party keyboards don't work on the IIgs, but you can mix and
match the IIgs keyboard, "Apple Standard Keyboard", "Apple Extended
Keyboard" and "Apple Extended Keyboard II".

> 4) What does 'Woz limited edition' mean?  

The first few thousand Apple IIgs machines off the production line were
stamped with this legend.  The consensus here is was probably the first
50,000.  (About one million IIgs machines were made over its entire
lifetime.)

Being the oldest model of the IIgs, it is most likely to be suffering
from a flat battery, and may have the original firmware ("ROM 00") and a
faulty video graphics controller chip (the fault causes a flickering
display in monochrome double hi-res graphics mode, and in some machines
also in 80-column text mode, with varying behaviour depending on the
text colours chosen).

The ROM and VGC were free upgrades in 1997 but are no longer available.

> 5) How do I determine the ROM version of my IIgs?

When you turn it on, you get a beep and "Apple IIgs" displayed at the
top of the text screen.

If that is all it says, then you have the original firmware ("ROM 00").

If it has later firmware, then there will also be a copyright message at
the bottom of the startup screen, and the last line will say either "ROM
Version 01" or "ROM Version  3".

A ROM 3 machine actually has a revised motherboard, with extra RAM and
ROM, and a few other tweaks.  You cannot "upgrade" to a ROM 3, short of
replacing the motherboard.

ROM 0 can be upgraded to ROM 1 by swapping the chip, if you can get one.

The main disadvantage of ROM 0 is that it isn't supported by recent
system software (System 4.0 or later requires ROM 1 or 3), and most
recent native IIgs applications require at least System 5.0 (and at
least 1 MB RAM).


> My IIe spontaneously "shuts off" after random up times, ranging from 5
> seconds to 2 hours.  I have to turn it off, wait 5 seconds, then turn it
> back on the recover.  Nothing seems warm.  After many such episodes, I
> have linked this fault to when the computer chassis gets slightly
> bumped, like when inserting/removing disks from the 5.25" drive, which
> sits on top of the IIe chassis.  All the wires inside seem snug.  Ideas
> on how to fix this?

It sounds like the power supply is cutting out to protect against
overloading, perhaps due to a borderline short.

Switch the machine off, remove all the cards, and check that there isn't
any debris in the slots, on the motherboard, or on the slot card
connectors.

It might also be an electrical fault in the 5.25" drive.