Re: Will IBM 360 Floppies work in Apple ][ Drives?

[pausch@saaf.se (Paul Schlyter)]

In article <1htvwo7.i7wl3av17mrN%dempson@actrix.gen.nz>,
David Empson <dempson@actrix.gen.nz> wrote:

> Paul Schlyter <pausch@saaf.se> wrote:
> 
>> In article <C-KdnaXNzue_10bYnZ2dnUVZ_riknZ2d@giganews.com>,
>> Scott Alfter <scott@alfter.DIESPAMMERSDIE.us> wrote:
>>> In article <1171893268.411041.183420@l53g2000cwa.googlegroups.com>,
>>> KPR <krauer@rpmtec.com> wrote:
>>>> Will IBM 360 Floppies work in Apple ][ Drives?
>>>>
>>>> I finnaly cleand up my basement and have about 400+  5 1/4 IMB 360k
>>>> Floppies..
>>>
>>> At first, your subject line brought up the thought "floppies for a
>>> System/360?"    Leaving off the "K" from "360K" had that effect.
>>>
>>> The weird thing is that I'm nowhere near old enough to have ever used one of
>>> those beasts. :-) 
>> 
>> You should be happy for that!  :-)
>> 
>>> I suspect they never used floppy disks of any sort, let
>>> alone 5.25" floppies.
>> 
>> Actually, the floppy was invented by IBM, back in the early 1970's.
>> The first floppes were 8" floppies though, holding some 240 KBytes
>> each (8" SSSD = Single Sided Single Density).
> 
> I used the standard IBM 8" SSSD floppy disks on a CP/M system in the mid
> 80s. If memory serves, it had 40 tracks, 32 sectors per track, 128 bytes
> per sector, which would be 160 KB. Other systems might have used a more
> efficient format with more bytes per sector (fewer gaps) and squeezed in
> a little more per track, but I doubt they could have got 240 KB out of
> it.
> 
> The same system supported DSDD 8" floppies, which used a double sided,
> 77 track, 17 sector, 512 byte format (1.3 MB).
>
> The double density formats were highly variable and machine-specific,
> but the SSSD 8" format was the official and original standard for
> distribution of CP/M from Digital Research, and was intended to be used
> as a cross-platform compatible format (as long as 8" drives were
> available for that platform).
> 
> CP/M on an Apple II made things difficult by only using the Apple II
> 5.25" format, which meant software developers had to jump through some
> hoops to get software onto the Apple II CP/M disks in the first place if
> they were selling CP/M software for other systems.

At the job I had in the mid 1980's, they bought an Apple II for data
acquisition, and added an extra 8" double floppy drive, mostly to get
larger floppy capacity than the 140K which the Apple II's own floppy
format offered.  Drivers for Apple DOS 3.3 and Apple CP/M came with
that 8" floppy drive.  This enabled me to buy CP/M software on 8" SSSD
disks and then transfer the files to Apple II floppies with just a
file copy command from an 8" disk volume to a 5.25" disk volume.  Much
easier than hooking up two computers through a serial line... :-)

I then switched jobs, ceased using CP/M, and that Apple II is probably
gone now since a long time - don't know what happened to it.


> The original transfer of the CP/M operating system to the Apple II
> platform may have been done using an 8" disk drive and controller card.
> Alternatively, DOS 3.3 might have been used as a go-between to copy the
> OS and system applications from another platform.
> 
> After a working CP/M system was running on the Z80 card with a basic set
> of tools, it would be possible to use serial ports to transfer other
> files from a "standard" CP/M system, e.g. via XModem. The original
> XModem implementation is ideally suited for transferring CP/M files, as
> both use a 128 byte sector size and don't care about the exact number of
> bytes in the file.
> 
> -- 
> David Empson
> dempson@actrix.gen.nz
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