LIF questions

[J-F Garnier]

(03-22-2023 03:53 AM)brouhaha Wrote:  

(03-21-2023 11:16 AM)J-F Garnier Wrote:  Then, you should know that the HP-41C can only manage 128kB volume with the standard functions of the HP-IL module

Isn't that 41C 128KiB limit just for initializing the medium? I recall using something like 630KiB with 9114 floppy drives without any issues other than initialization. The 82183A Extended I/O module allows initializing a medium larger than 128KiB, using a program in the "HP 9114A Using Your Disk Drive" manual (User's Library program #41-09114).

There's probably some other limit to what the 41C HP-IL firmware can handle. IIRC, a few megabytes works, but since there's only a flat directory, it's going to get quite unweildy.

It's not just about initializing, otherwise it would be easy to initialize a disk with the 71B then use the full capacity with the 41.
The problem is that the 41C doesn't use the disk descriptor in sector 0, so *always* assumes the volume is 128kB (the size of the 82161 cassettes) when creating new entries in the catalog.
However, if a file is already existing beyond the 128kB, the 41C can access it (read and re-write). This was the purpose of the utility provided by HP in the 9114 manual: create a directory entry beyond 128KB.
In the same way, the Extended-IL module provides new functions for creating files, but regular HP-IL functions are still used for reading.

My experience showed that volumes up to 1MB can be used with the Extended-IL. IIRC, this module also doesn't use the disk descriptor, but just tries to access sectors up to 1MB, to find out the capacity of the disc.

Edit: quote from the Extended-IL manual:
"All of the write functions in the HP-IL module have been modified to allow their use on mass storage devices of up to 1 megabyte."
See also the addendum with the SNEWM bug.

J-F