- SCSI disks with 20M 1280-byte blocks work
- SCSI disks with 25M 1280-byte blocks work
- SCSI disks with 28M 1280-byte blocks work
- SCSI disks with 28,870,145 1280-byte blocks works
Both Narrow and Wide single-ended SCSI drives work - the wide ones with appropriate
Chances are I was having problems with the full ~28.9M blocks initially because I didn't power-off reboot the XL1201 after the full .
I have a Seagate Barracuda ST336918N, a 50-pin narrow SCSI drive which is formatted at 1,280 byte blocks. Unfortunately, the XL1201 cannot create an FEP filesystem.
I also have a Seagate Cheetah ST318451LW, a 68-pin wide differential SCSI drive that boots and runs Genera just fine.
I wonder if there is some sort of cutoff in the FEP filesystem that indicates a certain maximum size, or if it's in the SCSI interface hardware, or what.
One obvious cutoff point here is 2^24 blocks (16,777,216) if there is a block count limit. That would be 3 bytes to specify any block number.
(By the way, the Linux sg3_utils is the ultimate tool for working with these drives.)
As a first test, I'm going to try 20,000,000 blocks and see if that works.
linux:~# sg_format --resize --count=20000000 -vvv /dev/sdc ... lots of output ... Resize operation seems to have been successful
We can check with
sg_readcap and indeed, it looks good. Now it says:
... Last logical block addresss=19999999 (0x1312cff), Number of blocks=20000000 Logical block length=1280 bytes Hence Device size: 25600000000 bytes, 24414.1 MiB, 25.60 GB
Now, I have to put the drive back into the Symbolics XL1201 and test it.
Booting Genera 8.3 it shows up as:
SCSI address 1 on controller 0: SEAGATE ST336918N 0003, direct access, 20000000 blocks of 1280 bytes (24G bytes total).
Then, I'm able to create a FEP filesystem with no problem! Let's see what the
Show Directory says. Note that this takes a very long time you first access a FEP filesystem with
Disk Wait and a flashing underline in the status bar; I assume it's caching details about the FEP filesystem in RAM as subsequent
Show Directory commands run very quickly.
Command: Create Initial Fep Filesystem (FEP unit number) 8 Command: Show Directory (...) FEP8:>*.*.newest FEP8:>*.*.newest 19997910 free, 2090/20000000 used (0%) ...
So, evidently 20M blocks works but ~28.9M blocks doesn't. So, let's try again with 25M blocks.
It seems to have worked with 25M blocks (but I forgot to take a picture). One difference is that it warned me that I already had an FEP filesystem before allowing me to overwrite it.
So, let's try a third time with 28M (exactly) blocks. This one worked this time (and I took pics). So, let's try one more time with the full disk size restored...
linux:~# sg_format --resize --count=-1 -vvv /dev/sdb
(Yes, I changed other devices on the SCSI chain in Linux so it became
Well, the full disk size
Create Initial FEP Filesystem command worked too.