The CBM DOS can write “relative data” onto disk, based on individual records. The advantage is that all space is allocated once and then randomly accessed if and when it’s needed – much like the tracks on a CD. This approach is different from sequential files, which have to read or write the whole file … Read more
Sequential files are files to which we can write arbitrary data and read it back later. We can even append data to the file later without having to re-write the whole file. This works with the Datasette (tape drive) as well as floppy drives. Here’s how to do it in CBM BASIC 7.0: Creating Sequential … Read more
The Commodore 1571 floppy drive powers up in compatibility mode and behaves just like a 1541 drive – unless a C128 is connected and sends it a fast serial transfer. They did this because otherwise the drive wouldn’t be compatible with the C64 and Plus/4. The C128 speaks to its attached disk drive when we … Read more
Here’s a quick word splitter routine for CBM BASIC. It takes phrase and “explodes” all words into an array, removing spaces. Feel free to adopt it for your own needs. 10 rem word splitter 20 rem splits a long phrase into words at a space 30 input “tell me something”;a$ 40 rem clear current array … Read more
When I had a C64 back in the days, the only IF/THEN statement we could create in BASIC v2 was just that: IF and THEN. There was no ELSE, and everything had to be on a single line. It was the only flow control we had back in those days, and it was a severe … Read more
I’ve ordered an SD2IEC a few weeks ago from Nic over at The Future was 8 Bit. It’s an SD card reader for Commodore computers and emulates many features of the 1541 Floppy Disk Drive. I went for the Limited Edition made from authentic recycled C64 plastic – so this little critter used to be … Read more
Sadly the Commodore machines don’t offer a routine to locate or set the current cursor position via BASIC. There is however a Kernel routine named PLOT which can do this in Machine Language. Here’s how we can utilise it. Getting the Cursor Position . 01300 38 sec . 01301 20 f0 ff jsr $fff0 . … Read more
You can merge / combine / concatenate BASIC programmes on a Commodore computer. It’s often useful to develop shorter chunks of code and put them together for a larger app. Sadly there’s no built-in command that lets you do this, even though the C128 user guide hints that the CONCAT command can do this (if … Read more
