3152 BYTES FREE ??

carlsson · Post by **carlsson** » Sat Apr 15, 2006 6:20 pm

I followed a link to some minor (?) German C= site which advertised themselves with screenshots of VIC-20, C64 and C128. They don't have much content, but in the VIC section some links to other sites: Café VIC, PWP misspelt as PMP and so on. No Denial link though.

http://www.donchaos.com/index.php?optio ... &Itemid=32

What stirs my interest is the VIC-20 startup picture they have used; it says 3152 BYTES FREE. That is a very odd number to me, not even Super Expander sans the 3K expansion would use 431 bytes extra (it uses 136 bytes, i.e. 3447 bytes free w/o 3K expansion). I'm not sure if the picture was grabbed from an emulator or a real VIC, but in either case, it reminds me of a VIC with bad RAM chips or customized via POKEs to lower RAMTOP. But why? Does anyone recognize this memory setting?

Post by **Jeff-20** » Sat Apr 15, 2006 7:42 pm

First, they need a Denial link. :p

As for the memory, this is very interesting. I would love to hear theories from users in other regions. Was this standard in any area?

Boray · Post by **Boray** » Sun Apr 16, 2006 6:03 am

Maybe they use some other utility cartridge that uses some ram to patch the system...

carlsson · Post by **carlsson** » Sun Apr 16, 2006 8:18 am

I went through the tool ROMs on ftp. The following modules use RAM:

Super Expander: 136 bytes
Programmers' Aid: 120 bytes
Basic V5: 120 bytes (and funny sounds on error messages)
ExBASIC L2: 80 bytes (includes commands like COKE and DISPOSE)
PET Loader: 6790 bytes (a 40 col PET simulator, requires +8K RAM)

I realize it is possible to obtain 3152 bytes, but not sure why. If the screen shot comes from an emulator, it is unlikely that the emulator had bad RAM chips.

POKE55,81:POKE56,28:SYS58238

carlsson · Post by **carlsson** » Sun Apr 16, 2006 8:23 am

POKE55,3:POKE56,16:SYS58238