Hepax module memory storage

Discussion about the new DM41X calculator
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danielCL
Posts: 29
Joined: Mon Jul 26, 2021 3:53 pm

Hepax module memory storage

Post by danielCL »

Dear All, just wondering why hepax ram only got 1304 from HEPROOM. According to hepax user manual, it should be something around 8000 register. Do I miss anything or misunderstand the user manual ?

Quote from user manual:

"Of the 8192 words in the Standard HEPAX and HEPAX Memory modules, 340 words are used internally by the HP-41 itself and the HEPAX file system –leaving 7852 words available to the User. The Advanced HEPAX and HEPAX Double Memory modules contain twice as much memory."

Regards!
whuyse
Posts: 172
Joined: Thu Dec 21, 2017 1:23 pm

Re: Hepax module memory storage

Post by whuyse »

HEPROOM is expressed in registers, not words.
From the same manual:

'A data file is a collection of HEPAX data registers. Each register will hold one number or 6 characters of text – just like a main memory data register.
Recall that one register in main memory is seven bytes = 7 x 8 bits = 56 bits. Six HEPAX words is 6 x 10 bits = 60 bits. You see that six HEPAX words is enough to store 7 bytes. To get the most from HEPAX memory, we therefore store data in HEPAX data registers that consist of only six words.'

and 7852 words divided by 6 = 1308 registers. Not sure were the 4 other registers are used (file stub probably, a bit like the .END. in program space).

Cheers, Werner
42S #3249S01123
DM42 #00345
DM41X #01215
danielCL
Posts: 29
Joined: Mon Jul 26, 2021 3:53 pm

Re: Hepax module memory storage

Post by danielCL »

Thanks for the explanation !

Cheers !
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