15 Jun
2016
15 Jun
'16
11:47 a.m.
On older Apple 68k machines, having an Apple-branded CDROM means you can
be assured it'll boot (though it's rumored that many generic SCSI CDROMs
work for booting) and also that it'll "just work" on most of the OSs.
I'm guessing it's a simple check to see if the vendor in the firmware is
"APPLE". Has anyone ever managed to hack the firmware of something like a
Yamaha, Pioneer, or Plextor drive so that it lies and says it's "APPLE"
thus being fully enabled by the OS & hardware ? Does anyone know anything
about flashing CDROM firmware and the dynamics of such things? I wonder if
it'd just be a matter of a simple hexedit/byte-patch on the firmware image
then load it up... Is this a bogus idea?
The reason for this is that if it's possible, I could buy a Pioneer slot
loading SCSI CDROM drive, stuff it into my Quadra 660AV, and then hack it
to "just work" instead of needing drivers et al. The slot cover isn't big
enough for a normal tray-drive CDROM to work. Thus I can only use a CD300i
caddy-based drive (or theoretically - a slot drive). My 300i is a bit of
PoS and even after I cleaned it, the thing still has a lot of read
problems.
-Swift
15 Jun
15 Jun
12:42 p.m.
On older Apple 68k machines, having an Apple-branded
CDROM means you can
be assured it'll boot (though it's rumored that many generic SCSI CDROMs
work for booting) and also that it'll "just work" on most of the OSs.
I'm not sure if it has anything to do with it, but over on the early SGI
and Sun and NeXT stuff you had to change the block size on the CD-ROM to
get them to work. The early Toshiba drives had solder pads that could be
split open or re-closed to change block sizes and such to get them to work
on all of the different hardware types.
--
Ethan O'Toole
1:45 p.m.
On Wed, 15 Jun 2016, ethan at 757.org wrote:
I'm not sure if it has anything to do with it, but
over on the early SGI
and Sun and NeXT stuff you had to change the block size on the CD-ROM to
get them to work.
Yeah, I think you mean the 2048 vs 512 byte block size. SGI's use a 512
byte size, IIRC. Folks were just talking about that a few weeks back, in
fact.
The early Toshiba drives had solder pads that could be
split open or
re-closed to change block sizes and such to get them to work on all of
the different hardware types.
Most SCSI-based Yamaha and Pioneer drives have a jumper you can set for
it. However, I tried this with my Pioneer SCSI CDROM and it still didn't
work. I guess if nobody knows I can figure out how to run a
debugger/syscall-profiler of some kind on MacOS 8.1 and fire up Disk Setup
and see what it's actually looking for. My guess is it's just checking to
make sure the SCSI vendor ID is "Apple" and then happily goes on with it's
job. However, I just don't know for sure yet.
I also don't know if altering a ROM image like that would have disastrous
effects if, for example, the ROM image is appended with a CRC32 checksum
that will fail once I flash it with a hacked image. I also am not sure if
I can find the right spot in the firmware image to do the byte-patch. Lots
of unknowns, so that's why I'm seeking the advice.
-Swift
2:13 p.m.
Didn't hacked or 3rd party cd-rom drivers exist. That won't handle the
boot problem, but the boot checks might not be as thorough as Disk Setup
???
Plextor CD-ROM SCSI drives used to have a 512 byte block jumper as
well. I don't know about the DVD drives.
On 2016-06-15 16:45, Swift Griggs wrote:
On Wed, 15 Jun 2016, ethan at 757.org wrote:
I'm not sure if it has anything to do with
it, but over on the early
SGI
and Sun and NeXT stuff you had to change the block size on the
CD-ROM to
get them to work.
Yeah, I think you mean the 2048 vs 512 byte block size. SGI's use a
512
byte size, IIRC. Folks were just talking about that a few weeks back,
in
fact.
The early Toshiba drives had solder pads that
could be split open or
re-closed to change block sizes and such to get them to work on all
of
the different hardware types.
Most SCSI-based Yamaha and Pioneer drives have a jumper you can set
for
it. However, I tried this with my Pioneer SCSI CDROM and it still
didn't
work. I guess if nobody knows I can figure out how to run a
debugger/syscall-profiler of some kind on MacOS 8.1 and fire up Disk
Setup
and see what it's actually looking for. My guess is it's just
checking to
make sure the SCSI vendor ID is "Apple" and then happily goes on with
it's
job. However, I just don't know for sure yet.
I also don't know if altering a ROM image like that would have
disastrous
effects if, for example, the ROM image is appended with a CRC32
checksum
that will fail once I flash it with a hacked image. I also am not
sure if
I can find the right spot in the firmware image to do the byte-patch.
Lots
of unknowns, so that's why I'm seeking the advice.
-Swift
2:24 p.m.
On Wed, 15 Jun 2016, rescue wrote:
Didn't hacked or 3rd party cd-rom drivers exist?
I have some vague memory, but I was thinking that could just be wishful /
convenient memory on my part.
That won't handle the boot problem, but the boot
checks might not be as
thorough as Disk Setup ???
Well, my 660AV will boot from a Yamaha drive I have. However, MacOS
refuses to show the drive after it's installed. So, I'm thinking that a
hack such as the one we are discussing might be a full fledged solution.
Plextor CD-ROM SCSI drives used to have a 512 byte
block jumper as well.
I don't know about the DVD drives.
Plextor makes some great gear. However, I've also had good luck with
Yamaha. I have had trouble with Pioneer, but they make the only slot-CDROM
(and DVD) drives I know of. Their metal USB drives are also nicely built,
pretty, and have a cool design. However, they've been less robust than
some others I own (I have an LG drive with much fewer read errors and it's
actually slot-driven, too).
-Swift
2:56 p.m.
Don't have time to fully check it out, but check out:
http://chrislawson.net/writing/macdaniel/2k1130cl.shtml
On 2016-06-15 17:24, Swift Griggs wrote:
On Wed, 15 Jun 2016, rescue wrote:
Didn't hacked or 3rd party cd-rom drivers
exist?
I have some vague memory, but I was thinking that could just be
wishful /
convenient memory on my part.
That won't handle the boot problem, but the
boot checks might not be
as
thorough as Disk Setup ???
Well, my 660AV will boot from a Yamaha drive I have. However, MacOS
refuses to show the drive after it's installed. So, I'm thinking that
a
hack such as the one we are discussing might be a full fledged
solution.
Plextor CD-ROM SCSI drives used to have a 512
byte block jumper as
well.
I don't know about the DVD drives.
Plextor makes some great gear. However, I've also had good luck with
Yamaha. I have had trouble with Pioneer, but they make the only
slot-CDROM
(and DVD) drives I know of. Their metal USB drives are also nicely
built,
pretty, and have a cool design. However, they've been less robust
than
some others I own (I have an LG drive with much fewer read errors and
it's
actually slot-driven, too).
-Swift
3:02 p.m.
On Wed, 15 Jun 2016, rescue wrote:
Don't have time to fully check it out, but check
out:
http://chrislawson.net/writing/macdaniel/2k1130cl.shtml
Thanks. That doc mirrors my current understanding, but it doesn't address
the ROM hack I'm contemplating.
-Swift
3:05 p.m.
Your going to need a CDROM that can be set for 512 byte sectors. We use to
use Plextor drives
and if money was a factor, Pioneer. In the early days Plextor drives were
quite a bit more expensive
the all the others, and where usually faster.
BTW 512 bytes came from the sector size of a hard drive
On Wed, Jun 15, 2016 at 11:47 AM, Swift Griggs <swiftgriggs at gmail.com>
wrote:
On older Apple 68k machines, having an Apple-branded CDROM means you can
be assured it'll boot (though it's rumored that many generic SCSI CDROMs
work for booting) and also that it'll "just work" on most of the OSs.
I'm guessing it's a simple check to see if the vendor in the firmware is
"APPLE". Has anyone ever managed to hack the firmware of something like a
Yamaha, Pioneer, or Plextor drive so that it lies and says it's "APPLE"
thus being fully enabled by the OS & hardware ? Does anyone know anything
about flashing CDROM firmware and the dynamics of such things? I wonder if
it'd just be a matter of a simple hexedit/byte-patch on the firmware image
then load it up... Is this a bogus idea?
The reason for this is that if it's possible, I could buy a Pioneer slot
loading SCSI CDROM drive, stuff it into my Quadra 660AV, and then hack it
to "just work" instead of needing drivers et al. The slot cover isn't big
enough for a normal tray-drive CDROM to work. Thus I can only use a CD300i
caddy-based drive (or theoretically - a slot drive). My 300i is a bit of
PoS and even after I cleaned it, the thing still has a lot of read
problems.
-Swift
3112
days inactive
3112
days old
8 comments
4 participants
participants (4)
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ethan＠757.org -
pete＠petelancashire.com -
rescue＠hawkmountain.net -
swiftgriggs＠gmail.com