Xl1201

I recently set up a LAN of my three XL Symbolics machines at home. The XL1201 which was having stability issues has been largely stabilized (thanks to help from David Schmidt). I will post more about … »

One of the theories about the instability of my Symbolics XL1200 is that the CPU has no heatsink and so it is suffering from thermal problems after a while. (15-30-ish minutes) David K. Schmidt was … »

UPDATE: No joy. Still self-reboots. So, I put the Merlin II card back into the XL1201, connected the power and console, and powered it up. Nothing. Blank screen (which means the monitor was at least … »

UPDATE: I clipped and removed the broken capacitor. Replacing it will be the task of another day. I spent two days removing, cleaning and reseating each DIP chip on the Symbolics XL1201 Merlin II Main … »

To see if I can isolate the cause of the XL1201 instability, I am going to physically inspect the two main cards with a loupe and flashlight. If I see anything suspect, I’ll take a picture with … »

In an effort to rule out the power supply causing the XL1201’s instability, I sent it out for overhaul by Power Clinic. After reinstalling it, I booted the XL1201 and just let it sit in the … »

So, I learned something about the Todd MAX-354-1252 power supply in the Symbolics XL1201 today that I thought I’d share. Not that I understand it, mind you. The power supply has six trim pots. … »

Well, tonight I had more crashes using the XL1201. Each time the computer crashed after about 20 minutes. This indicates to me that there’s something odd going on somewhere. Before the first … »

Well, the instability on the XL1201 has been disheartening. However, I have a few suggestions and plans to see if I can figure it out. Kalman Reti would like to see backtraces to see if it’s a … »

I don’t have the time to post all the details before going to sleep, but I did a few things tonight including measure the power supply voltages, install new RAM, and have a lot of problems and … »

I was asked to provide a full list of all the files on the XL1201 Genera 8.3 hard drive I received from David K. Schmidt. Here they are in screenshot form from the first boot this past Thursday. »

I’m setting up Genera 8.3 on the XL1201 using a clean hard drive. Literally all this hard drive has on it is Genera 8.3 and these patches: Genera 8.3 y2k patches Copy world patch Fepfs patch … »

I was asked how much power is used by the XL1201. Here are a few data points… XL1201 with only SCSI2SD: 222-233W Console: 106W With the XL1201 sitting idle it takes the same amount as … »

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 … »

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 … »

UPDATED July 28, 2016: More mini-benchmark results added. I was asked to do a simple benchmark of the XL1201 by Jerome Ibanes and share the results. Here is his requested code: (defun fib(n) (if (or … »

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, … »

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 … »

The XL1201 now boots nicely from a new ST318451LW Cheetah drive that David K. Schmidt sent (sold) me. It loads FEP version 333 and a clean Genera 8.3 distribution world with just a few patches: Genera … »

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 … »

Attempting a clean install of Genera 8.3 on XL1201 using just a CD-ROM drive and a blank hard drive. However, from preliminary results, this seems to require a working Genera to install Genera again. … »