Scsi on Symbolics LISP Engineering

XL1201 and SCSI2SD v5 128GB

Sun, 26 Jun 2016 20:50:44 +0000

I’m attempting to use the SCSI2SD v5 with a 128G microSD card.

You can find out the size of an SD card attached to a modern Mac with diskutil list and then diskutil info /dev/disk8 (or whatever device it’s listed as). This microSD card is reported as:

# diskutil info /dev/disk8
 Device Identifier: disk8
 Device Node: /dev/disk8
 Whole: Yes
 Part of Whole: disk8
 Device / Media Name: SD USB_3_0 Read

 Volume Name: Not applicable (no file system)

 Mounted: Not applicable (no file system)

 File System: None

 Content (IOContent): None
 OS Can Be Installed: No
 Media Type: Generic
 Protocol: USB
 SMART Status: Not Supported

 Total Size: 127.1 GB (127103139840 Bytes) (exactly 248248320 512-Byte-Units)
 Volume Free Space: Not applicable (no file system)
 Device Block Size: 512 Bytes

 Read-Only Media: No
 Read-Only Volume: Not applicable (no file system)

 Device Location: External
 Removable Media: Yes
 Media Removal: Software-Activated

 Virtual: No
 OS 9 Drivers: No
 Low Level Format: Not supported

So, the microSD has 248,248,320 sectors.

SCSI 50 to 68-pin Adapters

Sun, 26 Jun 2016 04:52:17 +0000

Well, it seems that not all SCSI 50-pin female to 68 pin female adapters are created equally.

I bought several of these from Amazon, made by Monoprice. (Pictures below.) My SCSI chain in the XL1201 was then:

SCSI on Backplane -> 50-68 adapter -> cable -> ST318451LW -> cable (same cable) -> terminator

The terminator is built into the cable and is labeled “Foxconn Ultra 320.”

This was able to boot my SCSI2SD v5 card (with another 50-68 pin adapter) but not the ST318451LW.

XL1201 Known Working Disks

Fri, 24 Jun 2016 04:42:55 +0000

Note: After formatting a disk to 1280-byte blocks on Genera, make sure to hard power cycle reboot the computer before trying to use it for a FEP file system or any other purpose.

From my own trials, these drives work:

Seagate Barracuda ST336918N - 36G drive (up to 4,096 bytes/sector)
Seagate ST39173N - 9G drive
Seagate Cheetah ST19101W - Tall 9G drive

Per David K. Schmidt on June 23, 2016:

Seagate 18 GB drives known to work:
- Cheetah X15 ST318451LW
- ST118273N/W
- ST318416N/W
- ST318417N/W
- ST318418N/W

It seems that Seagate’s later SCSI drives will only format to 528 byte maximum block sizes per the PDF manuals. For example:

Large SCSI Disks and XL1201

Fri, 24 Jun 2016 02:57:49 +0000

TL;DR:

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 .

Details

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.

Broken SCSI Pin on XL1201

Fri, 24 Jun 2016 00:03:00 +0000

Well, I was installing a new hard drive into the XL1201 today and just before I connected the SCSI cable, I noticed a pin seemed to be missing on the 50-pin SCSI male connector on the backplane. On closer inspection, it’s definitely missing.

Fortunately, it seems to be pin 1, which is a Ground pin on both single-ended and differential SCSI. Since half the pins are ground on single-ended SCSI, that’s fine, and there are still quite a few ground pins on differential, so we’re fine. It’s the bottom left pin in the picture here.