Need info about Apple Widget drives

[Patrick Schaefer <PSchaefer@epost.de>]

This is somewhat off-topic, but perhaps there is anybody out there who
can help me?

Widget-10 is the hard disk drive Apple designed for their Lisa 2 series.
Basically, these drives use the old Apple /// ProFile protocol so they
can be used as a ProFile substitute. However, besides the regular
ProFile command set ($00 read, $01/$02 write), there is at least one
additional command, starting with $26. This is what I figured out using
my logic analyzer to monitor the protocol traffic:


  Widget Command 26h:

  26 00 01 00 00 C5 13              -> Hsk 22
  26 01 01 00 07 62 6E +532 bytes   -> Hsk 23
  26 01 01 00 00 2E A9 +532 bytes   -> Hsk 23
  26 00 3D 00 36 63 03              -> Hsk 22 8x
  26 00 01 00 00 2E AA              -> Hsk 22
     |      \ |  /  |
     |       \|/    checksum: NOT(byte0+...+byte5)
     |        block number
     00=read, 01=write

Byte 0 is always $26. I guess that the second byte is the command
itself, byte 3..5 is the block address and the last byte is a checksum.
but what does byte 2 mean? Is this the sector count, the number of
sectors to read? Widget answeres commands with byte 2 <> 01 with more
than one handshake, so $26 may be a read/write multiple - command. Any
ideas?

Are there more special Widget commands?

How are servo board adjustment and low level formatting performed with
these drives? The controller board has an additional ROM for the Z8,
therefore the program space restrictions that led to ProFile's RW
ROM/Formatter ROM do not apply. Are the formatting routines contained in
the controller ROM, and how are they invoked?



Because working Widget-10 (and ProFile) drives are nearly unaffordable
today (at least in Europe), I started to build a ProFile emulator.
IDEfile uses a regular IDE drive and a converter board (a 8031
microcontroller with DMA logic) to emulate up to seven "ProFile"
volumes. Up to now, emulation  of the 5MB and 10MB ProFile drives works
fine. Both Apple /// and Lisa accept the drive and boot from it. So my
main goal, to get a drive I can use to play with Lisa software, has been
achieved. However, to complete the thing, I would like to add support
for Widget-10 and Widget-20 partitions.


Patrick