Classic Computer Magazine Archive COMPUTE! ISSUE 47 / APRIL 1984 / PAGE 108

VIC Memory Requirements

Say a VIC program requires 11K, and you have only a 16K memory expansion cartridge. Will the program run with the extra memory, or are you required to use the exact memory needed?

My second question is about word processing. When typing with or using a word processor, do you actually need a printer? All I'd really like to do is store my information on disk.

Dwain Young

When a program or article states requires 11K, this means it needs 11K bytes of memory or more. Both the VIC and 64 have pointers that manage BASIC memory. Examples are memory locations 45 and 46, which point to the start of BASIC variables (the end of the BASIC program proper), and bytes 55 and 56, which point to the highest address used by BASIC. These pointers automatically manage the extra memory for you.

However, on the VIC you have another thing to consider—screen and color memory locations. In the unexpanded VIC, the screen, color, and BASIC memory areas start at locations 7680, 38400, and 4096, respectively. When you plug in a 3K expander (like the Super Expander cartridge), these locations do not change. However, when you plug in one of the larger expansion cartridges (like the 8K or the 16K), these memory locations do change, to 4096, 37888, and 4608, respectively.

This is important with programs that perform POKEs or PEEKs to color or screen memory. For example, a program that POKEs or PEEKs screen or color memory and states needs 3K expansion might not work with an 8K expander because of the relocation of these memory blocks.

On the other hand, a program written for the unexpanded VIC that contains no POKEs or PEEKs to screen or color memory should run with any memory expansion. If you LOAD a program and it doesn't run properly, simply turn off your VIC, change memory expansion cartridges, and reLOAD your program .This will not harm the BASIC program, Just be sure you SAVE your BASIC programs before turning off your VIC.

No, you don't need a printer to use that word processor, if onscreen viewing and storing the text to disk or tape are all you require.