NOVRAM 64 / HEPAX bug?

[M. Joury]

Hi All,

I often write programs to a dsik drive and then secure them so I wrote a little routine to aid in this.

01 LBL 'RWRTPS

02 UNSEC

03 LBL 'WRTPS

04 WRTP

05 SEC

06 END

Calling WRTPS writes and secures the program named in the ALPJA register. Calling RWRTPS updates a 'SECURED' program.

I have been using this little program for years. A few months ago I obtained a NOVRAM 64 and moved a lot of my utility programs (including this one) into HEPAX RAM. Unfortunately running this program out of HEPAX RAM does not work. The program as written to disk (at this point I am testing using PIL-BOX which is another variable since I don't want to trash a floppy with a lot of data on it) can not be read back in most cases (the file on disk is huge compared to the original program size) and in the few cases where you can read it back it is pretty much garbage.

Interestingly enough a little while ago I wrote a program to floppy and the floppy ended up being trashed beyond the point where I wrote the program. Can't read or write anything past that file (which was also trashed). At the time I thought that it was simply that the medium had worn out and thought nothing more about it. Now I am wondering if I used this rotuine out of HEPAX RAM and that was the cause. It has been too long ago now for me to be sure but that might have been the cause.

Has anyone encountered this bug or anything like it? Can anyone reproduce it (fair warning: *DON'T try this on a disk full of programs*)?

Cheers,

-Marwan

[J-F Garnier]

Hi,

I don't have a NOVRAM64 but I reproduced the bug in Emu41 with Hepax emulation.

I saved a test program with your WRTPS program from user memory to "X", then put your WRTPS program in the HEPAX memory with HSAVEP, and saved again the same test program to "X1", and here is the result:

NAME    TYPE     REGS

X       PR,S       78

X1      PR,S      171

Attempting to load the 2nd copy (X1) crashes the emulated HP41 operation (corrupted program chain).

I got the same behaviour using the W&W RAMBOX OS (still in Emu41 emulation) instead of HEPAX, so it seems that this bug is not related to the HEPAX itself.

Conclusion: don't run mass storage commands from ROM space!

Edited: 3 Nov 2012, 1:49 p.m.

[M. Joury]

Hi,

Sounds like the bug is in the mass storage commands as you suggest since it is showing up in more than one place. Thank you for your confirmation!

-Marwan