Re: 800k drives (was Re: Apple IIc)

[musjndx@gsusgi2.gsu.edu (Jonathan N. Deitch)]

Robert Sturges <rs43+@andrew.cmu.edu> writes:

>   I'm just now graduating to the //e from the ][+ (at work it's all
>Mac), and several incompatibilities have come up which perhaps an expert
>(maybe you!) might be able to answer straight away:

That's why we're here ... you won't get support anywhere else !!

>    1. I just got a (used) Unidisk and find that it's incompatible with
>any disk][ devices plugged in my //e at the same time. The scenario here
>was to convert DOS 3.3 files to Prodos, but no combination of slot
>locations seem to work. Is the Unidisk a bad actor in general? Would you
>know if there's another way to get an 800k floppy on a //e?

First of all, you need a Unidisk controller card.  Stick it in slot 5 and
attach (gee whiz ...) then Unidisk to it.  Put the standard disk II controller
in slot 6 and hook the 5.25 drives to it.  If you want to get really fancy,
you can replace the unidisk/unidisk controller with the Superdrive card and
a FDHD superdrive.  This'll give you 800k AND 1.44m 3.5" floppies.

With this setup, the 3.5 drives appear as 5,1 and 5,2 and the 5.25 drives
appear as 6,1 and 6,2.  On my //c, for instance, I have three unidisks and
two disk IIs ... 5.25's appear as 6,1 and 6,2 ... the first two unidisks 
appear as 5,1 and 5,2 and the //c ROM maps the third to 2,1.

>    2. The floppy drives and hard drives advertised in A+ seem a bit
>overpriced compared with similar IBM (shudder) equipment. Would you know
>of a DOS 3.3 - compatible peripheral card (and DOS patch) for this
>purpose? Seems that there'd be a ready market for it.

IBM drives are simple MFM format drives.  Apple drives use GCR (Group Code
Recording) which requires a variable speed motor depending on the current
track number.  MFM drives use a constant speed motor.  Apple drives also have
to support multiple formats and interleaves in on-board 'smart' hardware ...
MFM drives are non-intelligent devices.

Long and short : Apple drives have more processing horsepower and more mech-
anicals in them and IBM drives are cheaper and simpler.

>    3. Not be deterred, I experimented with converting DOS 3.3 files to
>Prodos with just my disk]['s and find my Applesoft compiler (TASC by
>Microsoft, c1981) can't access the source code, or write files, etc. Is
>there another compiler out there which is Prodos compatible?

Don't know ... don't deal with BASIC anymore except for quick hacks.

>    4. Finally, I was surprised to find that Prodos consumes almost all
>the space on a 143k floppy. Seems pretty silly to live with this. Am I
>missing something obvious?

Last I checked, the ProDOS system file was 38 blocks (each block is two
sectors or .5k) for a total of 17k in size ... neatly fitting into the
language card memory space.  Basic is probably similar in size.  This should
account for around 80 blocks on a 273 block (280-7 for system) device.

>Well, if this is too much to bother with, I won't blame you.

Have fun !

- Jonathan
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