Storage

The CompactFlash card is your disk. Programs you save there are still there next week; everything in memory disappears the moment the power does.

Disks on a card

One card holds 256 disks. Each disk is a megabyte and holds up to 16 files. You work on one disk at a time, and DISK n moves you to another:

DISK 1

OK

Think of them as 256 floppies in a box, not as folders — there's no nesting, and a file lives on exactly one of them. Disk 0 is where you start, and one disk is plenty until you've got more than sixteen things worth keeping.

Filenames are eight characters, a dot, and three more: INVADERS.BAS, SCORE.DAT, TITLE.SCR. Upper case, and always in quotes when you type them.

A card, 256 disks, sixteen files on each. Nothing nests.

Looking at what's there

DIR lists the current disk:

DIR
DISK 0
HELLO   .TXT 6
GREET   .BAS 13

OK

Name, extension, and size in bytes. The gap in the middle is just the name being padded out to eight characters.

Saving and loading

SAVE "name" writes the program you've got; LOAD "name" reads one back.

10 PRINT "HI"
SAVE "GREET.BAS"

OK

NEW
LOAD "GREET.BAS"

OK
LIST
10 PRINT "HI"

OK

NEW there wasn't ceremony — it proves the point. The program really did come back off the card.

Save early

There's no autosave and no undo. If you've been typing for twenty minutes, SAVE it now. SAVE "WORK.BAS" over the same name each time is fine.

Getting rid of a file

DEL "name":

DEL "GREET.BAS"

OK
DIR
DISK 0
HELLO   .TXT 6

OK

Formatting

A new card needs formatting before you can save to it, and FORMAT also empties a disk you want to reuse. It clears the current disk only — not the whole card — and it asks first:

FORMAT
ERASE DISK 0? (Y/N) Y

OK

Anything other than Y and nothing happens.

Saving things that aren't programs

SAVE and LOAD deal in BASIC programs. To read and write raw memory — a screen you've drawn, a set of characters you've designed, a saved game — there's BSAVE and BLOAD:

• BSAVE address, length, "name" writes length bytes starting at address.
• BLOAD address, "name" reads a file back into memory at address.

10 POKE 2560, 42
20 BSAVE 2560, 1, "SCORE.DAT"
30 POKE 2560, 0
40 BLOAD 2560, "SCORE.DAT"
50 PRINT "HIGH SCORE IS"; PEEK(2560)

RUN
HIGH SCORE IS 42

OK

Line 10 puts 42 in memory. Line 20 writes that one byte to the card. Line 30 wipes it. Line 40 reads it back, and line 50 proves it survived. That's the whole shape of a save-game file.

When there's no card

Every disk command checks for the card first and says so rather than hanging:

DIR

?NO DEVICE ERROR
OK

Reseat the card, or see When something's wrong.

Making cards on your computer

cffs builds and edits CompactFlash images from a Mac, PC or Linux box — create a card image, drop files into it, then write it to a real card or hand it straight to the emulator. It's the easiest way to move a big pile of programs onto a machine at once.