Re: Sider Hard Drive Bad Block

[marc@cxr_rs6000.med.ge.com (Marc Wolfgram)]

David Hunter:
>>On another note, how can I utilize the full ten megabytes that I supposedly
>>have rather than the 8-9Mb that's available?  I've heard that the harddrive
>>can be converted to a ProDOS drive rather than using the wacky Sider format>

Jay Krell:
>If you mean you have an old partitionable-by-OS Sider and you want it to be all
>ProDOS, I think you need a new ROM to do that.

There is a way to do a single, full-partition, Sider without a ROM upgrade if
you really want to know... It's not simple, but I've done it to 4 or 5 Siders
a bunch of years ago.

The Sider boot code lives in physical sector 0, and the parameter stuff is in
sector 1... This works well with ProDOS because, sectors 0 and 1 fit completely
within block 0, which is reserved for boot code.  I wrote a small ProDOS boot
loader that fit entirely in the first 256 bytes of block 0, leaving the second
page free for the parameter data that the original Sider controller ROM uses.

The key to being able to do this lays in the availability of three things...
  - a binary file named INSTALL PT 4 which is on the second side of the old
    Sider disks... This file can be BRUN from DOS 3.3.
  - a block editor that will let you read a block from a file on one disk and
    write it to any block on another disk.
  - my Sider ProDOS boot code, which I'll post in (gack) original S-C Assembler
    source form in the near future if you want it... (I can't FTP outside of
    my site, but the code _is_ small :)

The process involves going into INSTALL PT 4 through a back-door that lets you
manually set up partitioning structures so that you can map the ProDOS logical
block 0 to the Sider's physical sectors 0 and 1... loading the boot code into
the block editor and tweaking the second page of the block to match the Sider's
parameter data... writing the boot code/param data to logical block 0 of the
drive.  WARNING - IF YOU EVER ERASE THE VOLUME (with the Finder or another
utility) THE CUSTOM BOOT CODE AND PARTITION MAP WILL BE DESTROYED (<-disclamer:)

Let me know if you want to go through this pain and suffering... I can probably
assemble the required parts if I dig around.

Marc Wolfgram
AOL: M Wolfgram   GEnie: M.WOLFGRAM2   inet: marc@cxr_rs6000.med.ge.com
There are two ways to write bug-free code and only the third one works!