SCSI Voodoo and an error code, too

[MrFahrenheit]

I’ve been having a heck of a time trying to copy files from my backup media (9.1GB magneto optical disks) onto an internal SCSI hard disk.

The external MO drive is a Sony 5.25” drive, which has functioned just fine up until now. I have ruled out the drive because, I have two and I’ve tried both. Same problems.

The internal hard drive, I’ve also changed out once. First was a Hitachi 34GB u320 drive (with the proper adapter and terminators). That drive decided to stop working so I changed it for a Fujitsu 34GB u320 drive.

I’m running Mac OS 7.6.1 on an overclocked and recapped Mac LC475, with a real 68040 CPU rated for 40mhz. Heat sink applied.

I’ve had two different RAM SIMMs installed: a 128MB and a 16MB when I was needing to constantly turn it off and on again.

I have the MO disks formatted for HFS and I’ve copied CD ISO files to them. I’m using Toast CD 4.1.3 to mount them on the desktop as a virtual disk, and I’m copying the contents over to the internal SCSI drive.

Before you ask, external device is SCSI ID 2, internal drive is 0. Termination exists on the internal bus at the SCA80 to 50 converter and I have a termination block on the external MO drive. No other devices.

I’ve changed the terminator and the external and internal drives and the SCSI cables.

I get random freezes, but only during Finder file copies. It will run for hours on end without issue. Randomly, it will freeze at some point during a copy and I have to turn the machine off and on. The mouse pointer moves but nothing else is happening.

The board was nice and clean prior to recapping and it’s nice and clean after. It has worked flawlessly for years until this event.

The last freeze caused the partition I was copying to not to mount on reboot. I got an error type -127 (see screen).

I tried deleting and recreating the partition with FWB HDT 3.0.2 but it crashes to the desktop.

Any suggestions ?

 

[ymk]

Has your overclocking also affected the bus speed?

 

[MrFahrenheit]

Has your overclocking also affected the bus speed?

The LC475 25mhz to 33mhz overclock affects the entire system.

 

[joshc]

At this point I would try a different machine. Have you got a G3 or G4 with a SCSI card? Or are you doing it on the 475 for a specific reason?

 

[MrFahrenheit]

At this point I would try a different machine. Have you got a G3 or G4 with a SCSI card? Or are you doing it on the 475 for a specific reason?

Well, my LC475 is my main “68k” machine. I’m copying and trying out software from System 6 and early System 7 days. Software which doesn’t play well with anything above Mac OS 7.6 a lot of times, which is why I’m using this particular machine. Also, it’s at my bar, which is very nice and quiet and accessible. I don’t have room here for anything besides a pizza box.

 

[MrFahrenheit]

I’ve decided to try a different hard disk driver for my internal drive. I installed Software Architect’s Disk Drive Tune-Up! Version 3.14, which supports 68k and PowerPC Upto OS 9.2.2 and I have installed 8.1 on the drive to see if I can reproduce it using new driver and OS version.

 

[ymk]

The LC475 25mhz to 33mhz overclock affects the entire system.

Ok, I thought it might have been running at 40MHz.

You can try removing the internal drive's termination as long as the external drive is terminated.

 

[MrFahrenheit]

Ok, I thought it might have been running at 40MHz.

You can try removing the internal drive's termination as long as the external drive is terminated.

I'm using a SCA80 to 50 pin adapter, which has built-in (soldered on) termination. In my experience, you cannot use an internal drive unless it has termination on the internal bus.

 

[ymk]

In my experience, you cannot use an internal drive unless it has termination on the internal bus.

By itself, no. With an external terminated device yes. The external bus is an extension of the internal.

Also, make sure the internal drive has no termination. If it has resistor nets, they should be removed.

Otherwise there's double termination.

 

[ymk]

To clarify, removing the internal termination isn't proper or normally recommended.

I understand now that it's not possible with your adapter.

 

[joshc]

This feels like a case where a SCSI sniffer would be useuful, perhaps. If it is actually a termination or other SCSI bus issue. Guessing you don't have one @MrFahrenheit ?

 

[MrFahrenheit]

This feels like a case where a SCSI sniffer would be useuful, perhaps. If it is actually a termination or other SCSI bus issue. Guessing you don't have one @MrFahrenheit ?

What would you recommend for a “SCSI Sniffer”? I don’t know what you mean, specifically.

 

[joshc]

What would you recommend for a “SCSI Sniffer”? I don’t know what you mean, specifically.

They come up on eBay now and again. They give you an indication as to what is actually happening on the SCSI bus. I haven't used mine yet but that's my understanding.



Mine looks like that and this is the general description of what it does:

'Thank you for purchasing SCSI POWER SNIFFER. Operating in any SCSI environment,
either Apple or IBM compatible, these two types of sniffers contain various specs that are
SCSI-1, SCSI-2 and SCS-3 compatible. Overall, these two products consist of FPT (Forced
Perfect Terminator), which means active terminator. With this, signal voltage on SCSI Bus is
regulated, each cable length can be extended to 80 feet, and the cable impedance for the
whole chain will be matched. Users can pin point disruptions in the chain through LED
indicators shown on the sniffer.'

 

[Phipli]

They come up on eBay now and again. They give you an indication as to what is actually happening on the SCSI bus. I haven't used mine yet but that's my understanding.

View attachment 52996

Mine looks like that and this is the general description of what it does:

'Thank you for purchasing SCSI POWER SNIFFER. Operating in any SCSI environment,
either Apple or IBM compatible, these two types of sniffers contain various specs that are
SCSI-1, SCSI-2 and SCS-3 compatible. Overall, these two products consist of FPT (Forced
Perfect Terminator), which means active terminator. With this, signal voltage on SCSI Bus is
regulated, each cable length can be extended to 80 feet, and the cable impedance for the
whole chain will be matched. Users can pin point disruptions in the chain through LED
indicators shown on the sniffer.'

Lol. Plug it in and see.

They're only good for "there is scsi" and "there isn't scsi".

This is mine in use, at super slow motion. In reality it is just a blur of lights that all look like they're on.

 

[joshc]

Lol. Plug it in and see.

They're only good for "there is scsi" and "there isn't scsi".

This is mine in use, at super slow motion. In reality it is just a blur of lights that all look like they're on.

OK, well...that's... both hilarious and very disappointing at the same time. At least it didn't cost me much.

 

[Phipli]

OK, well...that's... both hilarious and very disappointing at the same time. At least it didn't cost me much.

Someone sent me mine instead of a terminator. Had to take it apart and compared it with a circuit diagram of a terminator before they stopped trying to tell me it was a terminator. Got a refund, but never got the terminator I ordered

I guess it is my most bling scsi peripheral.

 

[Trash80toHP_Mini]

trag's tome is no longer pinned at the top of the list, might be helpful to many if not here:

SCSI Voodoo HowTo

I saw JT's mention of the need for this thread here: http://68kmla.org/forums/viewtopic.php?p=163030#p163030 so I decided to start rolling that ball. I posted a lot about this topic back in the 90s in the comp.sys.mac.* hierarchy in the news groups, so at first, I'm just going to quote some...

68kmla.org

 

[MrFahrenheit]

I seem to have solved my freezing issues.

1. I formatted the disk using Software Architect’s Disk Drive Tune-Up! 3.14
2. I installed Mac OS 8.1
3. I changed out 128MB EDO for 32MB FPM
4. I swapped logic boards for a different one, which is not overclocked
5. I enabled virtual memory (as having 36MB and copying from the mounted CD images was leaving not much available RAM to the Finder)

So far it seems stable.

 

[joshc]

I seem to have solved my freezing issues.

1. I formatted the disk using Software Architect’s Disk Drive Tune-Up! 3.14
2. I installed Mac OS 8.1
3. I changed out 128MB EDO for 32MB FPM
4. I swapped logic boards for a different one, which is not overclocked
5. I enabled virtual memory (as having 36MB and copying from the mounted CD images was leaving not much available RAM to the Finder)

So far it seems stable.

That's a lot of things to change, so I wonder which one 'fixed' it?

 

[3lectr1cPPC]

So you’re telling me there’s a device called a “SCSI sniffer”? And I didn’t know about it until now? Now I’ve gotta have one, that’s the best name ever!