From Integer BASIC to Applesoft

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The first Apple ][ had Wozniak’s Integer BASIC in its ROM: fast, and made for the colour graphics, but counting only in whole numbers, from -32767 to 32767. A program about money, or about anything with a decimal point, needed more. Apple went to Microsoft, which had a BASIC for the 6502 with floating point, and in August 1977 paid the first half of a licence for it. Apple added the graphics commands of its machine, and called it Applesoft.

It came first on cassette, at the end of 1977: a program that Integer BASIC loaded and ran, and that then took its place, in the memory of the machine. In 1979 the Apple ][+ had Applesoft in its ROM instead of Integer BASIC, at $1,195, less than the first Apple ][. The same year Apple Pascal came with the Language Card, 16 KB of memory for slot 0, which made an Apple ][ a computer of 64 KB. DOS 3.3, of 1980, loads into it the BASIC the ROM does not have: the two BASICs on one machine.

This page loads Applesoft from its tape into the first Apple ][, starts an Apple ][+ with Applesoft in its ROM and no Language Card, and then gives a Language Card to an Apple ][+ and to a first Apple ][, for the other BASIC. The prompt tells which BASIC is listening: > Integer BASIC, ] Applesoft.

What you need

k7_apple_600200600_applesoftiia.wav, the recording of Apple’s tape 600-2006-00, Applesoft IIa, from the Apple cassettes of the Brutal Deluxe cassette project, in a .zip of the same name;
DOS 3.3 System Master - 680-0210-A (1982).dsk, Apple’s DOS 3.3 System Master, on the Asimov archive.

./fetch-disks.sh in this repository downloads them into disks/ and checks them.

The Applesoft II Reference Manual of 1978, and the manual of the Language Card, are on the Internet Archive.

The machines

Four machines, the Language Card only in the last two.

The first Apple ][, with 48 KB, the ROM of Integer BASIC and the Monitor, and the tape of Applesoft in its cassette recorder; no Language Card:

izapple2 -model none -board 2plus -cpu 6502 -screen green \
    -rom "<internal>/341-000x_integer.rom" \
    -charrom "<internal>/Apple2rev7CharGen.rom" -forceCaps \
    -tape disks/k7_apple_600200600_applesoftiia.wav

An Apple ][+, with 48 KB and Applesoft in its ROM, and a Disk II controller in slot 6 with the System Master in drive 1; no Language Card:

izapple2 -model none -board 2plus -cpu 6502 -screen green \
    -rom "<internal>/Apple2_Plus.rom" \
    -charrom "<internal>/Apple2rev7CharGen.rom" -forceCaps \
    -s6 'diskii,disk1=disks/DOS 3.3 System Master - 680-0210-A (1982).dsk'

The same Apple ][+ with a Language Card in slot 0, 16 KB more:

izapple2 -model none -board 2plus -cpu 6502 -screen green \
    -rom "<internal>/Apple2_Plus.rom" \
    -charrom "<internal>/Apple2rev7CharGen.rom" -forceCaps \
    -s0 language \
    -s6 'diskii,disk1=disks/DOS 3.3 System Master - 680-0210-A (1982).dsk'

The first Apple ][ with a Language Card, and the same Disk II:

izapple2 -model none -board 2plus -cpu 6502 -screen green \
    -rom "<internal>/341-000x_integer.rom" \
    -charrom "<internal>/Apple2rev7CharGen.rom" -forceCaps \
    -s0 language \
    -s6 'diskii,disk1=disks/DOS 3.3 System Master - 680-0210-A (1982).dsk'

Integer BASIC

Start izapple2 with the first command. The first Apple ][ starts in the Monitor, *; press Control-B and Return for Integer BASIC, >. Type PRINT 7/2, PRINT 1/3 and PRINT 32767+1.

Three and a half is 3, a third is 0, and one more than 32767 is an error: Integer BASIC keeps each number in two bytes, a whole number.

Applesoft from the tape

Type LOAD: Integer BASIC loads Applesoft from the tape, as it would one of its own programs, 10,702 bytes. On the machine it took more than a minute; izapple2 plays the tape as fast as it can. Type RUN, and Applesoft takes over the machine, with its prompt, ]. Type the same three PRINTs, and PRINT SQR(2).

3.5, a third to nine figures, 32768, and the square root of two. The banner says Applesoft ][ Floating Point BASIC, April 1978, Apple’s copyright and Microsoft’s of 1976. It lives in the memory of the machine now: switched off, it is gone, and loading it again was a minute more.

Applesoft in the ROM

Quit izapple2 and start it with the second command, the Apple ][+ with no Language Card. It starts the disk by itself, and DOS 3.3 with Applesoft, from the ROM. Type PRINT 1/3, and INT, which asks DOS for Integer BASIC:

Applesoft answers at once, with no tape. But Integer BASIC is not in the ROM of the ][+ any more, and there is no room to load it.

The Language Card

The Language Card is 16 KB of memory, in slot 0, at the addresses of the ROM. DOS 3.3 loads into it the BASIC the ROM does not have, and switches between the two with INT and FP.

Quit izapple2 and start it with the third command, the same Apple ][+ with the card. As DOS 3.3 starts, the System Master loads Integer BASIC into the card, and says so for a few seconds:

Type PRINT 1/3, in Applesoft, then INT, which goes to Integer BASIC, PRINT 1/3 again, FP, back to Applesoft, and PRINT 1/3.

The prompt changes with the BASIC: > after INT, ] after FP. Programs written for Integer BASIC kept running on the new machine.
Quit izapple2 and start it with the last command, the first Apple ][ with the card. It starts in the Monitor; type 6, then Control-P, and Return to start the disk in slot 6. Here the System Master loads Applesoft into the card:

Type PRINT 1/3, in the Integer BASIC of the ROM, then FP, PRINT 1/3, INT and PRINT 1/3.

The same two BASICs, the other way round: the card held what the ROM lacked, and an owner of the first Apple ][ had Applesoft from the disk in seconds, instead of a minute of tape.

What next

Life with DOS 3.3 goes on with the System Master, and The Apple ][ of 1977 with the Monitor and Integer BASIC.