73 GB SCA SCSi harddisk and TT

[1ST1]

Hello, as I recieved some SCA-adapters and SCSI-terminators by mail today, I did a few tests with a 80 pin 73 GB SCA harddrive today. I found the follwoing combination almost working:

1. 50 pin to 68 pin SCSI adapter
2. 68 pin LVD U320 terminator
3. 68 pin to SCA adapter (no jumpers set), termpower added to pin 17+18 with a red wire (see photo)
4. IBM SCA SCSI 73 GB harddrive

The problem is, when the TT accesses the drive after reset, it is not found and the drive LED stays on. Then, when HDDriver starts from floppy, hangs uop when scanning the SCSI bus.

The following trick makes the drive almost working:
1. Attach drive to SCA adapter and terminator
2. Attach drive to power
3. don't attach TT scsi cable / 50-68 pin adapter to terminator
4. power up TT and wait until drive is ready (led off)
5. wait until TT starts to boot from floppy, and the quickly attach drive to SCSI cable
6. observe if hddriver detecs the drive, if not, start hddriver.prg from a:\auto, until it is detected.
7. start hdrutil, drive will be shown
8. create partitions
9. detach drive from scsi
10. make reset
11. repeat steps 5-6
12. open drive c:, d:, ..., it's there.

What could be the reason for TT's strange behaviour when it accesses the drive after reset?

http://img547.imageshack.us/img547/672/fp3b6.jpg

http://img850.imageshack.us/img850/8830/5n8s.jpg

http://img35.imageshack.us/img35/2678/6kyw.jpg

[uweseimet]

Well, TOS does not implement the SCSI bus protocol properly. Initiator identification is missing, SCSI messaging is not supported etc. Instead of letting the SCSI device control the bus, as required by the SCSI standard, TOS (like AHDI and most other drivers) tries to force its wrong ideas of what the drive should do next onto the drive. Most devices cope with this, but some don't. The newer the drive, the more likely TOS fails, and these problem have been well-known for a very long time.
Even though HDDRIVER fully supports the SCSI protocol including SCSI messaging (the NCR5380 is a regular SCSI chip with support for everything needed), the bus can remain blocked after TOS has screwed up the drive, and this is what you most likely observe.
Try to switch off drive features like disconnects, if the drive has jumpers for this. If you cannot switch off those features you may not be able to use this drive once TOS has tried to access it, or even once TOS has accessed any other device on the bus.

[1ST1]

Wouldn't that be an idea to patch TOS 3.06 and 4.04 in this matter? Anyone able to do this? I think this would open TT and Falcon to a lot more drives up to 300 GB (that seems to be the largest still available size.)

[uweseimet]

Patching TOS to support initiator identification might work. Patching for proper SCSI protocol support is so much work that I doubt anybody can/will do it.
Anyway, this should be discussed somewhere else but not in this forum, as it is not related to HDDRIVER.

[uweseimet]

For TOS 3.06 and 4.04 there is information available on what to patch for initiator identification, see below. Note that if you hardcode the computer's SCSI ID with such a patch you have to ensure that the same ID is saved to the NVRAM. When these IDs differ there may be problems. Also note that this patch may fix problems related to missing initiator identification in TOS, but does not fix the broken SCSI protocol handling of TOS. So this fix may work for some drives, or it may not, depending on which missing SCSI feature in TOS actually causes the bus to freeze.

http://phoenix.inf.upol.cz/~opichals/li ... &index=183

Initiator-Identifizierung ist nicht möglich, da nicht von Atari
reinprogrammiert.
Das TOS 3.06 kann diesbezüglich gepatcht werden, hierzu ist an der
Adresse $1C40 die Bytes auf die Werte $70 und $80 zu ändern.
Für das TOS 4.04 des Falcon030 gibt es auch einen Patch, hierzu
müssen an der Adresse $1C0E ebenfalls zwei Bytes geändert werden
und zwar ebenfalls auf $70 und $80.

Ist die Modifikation durchgeführt meldet sich der Computer auf der
SCSI ID7. Wichtig, es muß ab jetzt auch ein Festplattentreiber ver-
wendet werden der das Feature Initiator Identification unterstützt,
sonst schlägt der Bootvorgang wieder fehl!
Wenn das ungepatchte TOS einmal auf eine Fireball, etc. zugegriffen
hat, sperrt die Platte sich (und teilweise den ganzen SCSI-BUS) wegen
fehlender Initiator-ID für weitere Zugriffe, bis sie einen SCSI-Bus-
reset bekommt.

[1ST1]

I found now Quantum Maxtor Atlas 10K3 73GB SCA which is fully working! I have two of them. But as the chain (drive, SCA-adapter, terminator, 50-to-pin-adapter is too long, it is not possible to put this into the TT drive bay. I will keep my 9.1 GB drive inside the TT and put these Quantum 10K3 into an external case, together with DVD and ZIP drive.

Would be courious to know, if Maxtor 10K3 147GB and 10K3 300 GB also would work with TT and Falcon... Then I would be able to host all my collected Atari software, uncountable number of floppy disk images and so on directly on my TT...

The only disadvantage these Quantum Atlas 10K3 have, is that they are uncomfortably loud... The previously tested IBM 73 Gb drive is almost unhearable.