[LMH] Re: [LMH]Nevermore (well, exploiter actually)

[Mark J. Dulcey]

Brad Parker wrote:

  > I've also found someone who claims to have some T300 platters from a
> CADR and "wants them read".  Al Kossow has the only CADR I know of which
> might be able to read them - another adventure...

Why would you need a CADR to read them? Any machine with a working T300 
drive (admittedly a challenge to find in itself) should be able to get 
data from the platters. CADRs didn't really have a filesystem; the 
loadable "bands", or system images, were just stored in big contiguous 
blocks on the hard disk. (As an analogy, imagine a PC where the 
partition table is the only mechanism for carving up the hard disk.)

Actually, there were two LispM-native file systems developed at MIT; 
LMFS, written by people who later went to Symbolics, and FC, which I 
think was written by Richard Stallman. But the majority of CADRs didn't 
run either of them; files other than the bootable images were normally 
stored on other systems and loaded over Ethernet. The LispM knew about 
ITS (the Incompatible Timesharing System, a locally developed OS), 
Tenex, TOPS-20/Twenex, Unix, and Multics file syntax, as well as the two 
LispM-native file systems, and could open and close files over a network 
from any of them.

So a CADR may not have source code on its hard disk. At MIT, where they 
were developed, the sources were kept on a central TOPS-20 server, not 
on the CADRs themselves. At LMI, the Lambdas also got their source code 
from a central server, but the systems prepared for customers usually 
had a source code partition. That partition was handled by the 68000 
that acted as a system manager and I/O processor, not by the LispM 
itself; LMI didn't use a LispM-native file system on the Lambda. They 
DID use LMFS on the CADRs they manufactured; those are the most likely 
CADRs to have source code on their hard disks. I don't think Symbolics 
supplied full source code with the LM-2 CADR clones they built.