Glossary
Terms this guide uses, in the sense this guide uses them. Where a word means something slightly different in the wider world, that is noted.
ACIA — the serial chip, a 65C51. Turns bytes into the stream of pulses that goes down the serial cable, and back again.
ACE — All-in-one Computer Experience. The machine this guide is about: one board carrying the processor, memory, video, sound, storage, serial, clock, joystick ports and a full keyboard. See Your ACE.
ARMSID — the sound chip. A modern part that behaves like the MOS 6581 "SID" from the Commodore 64: three voices, real filters, RCA out.
bank — one 1 KB slice of the 512 KB of extra RAM. Only one is visible at a time, through a window at $8000. BANK n picks which. See Banked RAM.
BASIC — the language the machine boots into, and the program in ROM that runs it. Version 2.0 here. See Programming in BASIC.
BIOS — the whole 32 KB of ROM: Kernal, Monitor, BASIC and the character set together. This guide describes BIOS v1.5. Not the same sense as a PC's BIOS, which is only a boot loader.
CompactFlash — the storage card. Behaves as an 8-bit IDE drive; the BIOS divides it into 256 disks of 1 MB each. See Storage.
cartridge — a ROM on a small board that drops into the slot behind the keyboard and takes over $C000–$FFFF, replacing BASIC and the Monitor. See Writing a cartridge.
CP437 — the character set in ROM, from the original IBM PC. Box drawing, card suits, Greek letters, three densities of shading. See The character set.
cold start — power off and on again. Memory is cleared, BASIC starts from nothing. Compare warm start.
disk — one of the 256 1 MB partitions on the CompactFlash card, each holding up to sixteen files. DISK n selects one. Nothing to do with a spinning disk.
ECM — enhanced color mode. The F18A setting that turns pattern bits into color numbers, so a tile or a sprite can show four or eight colors instead of one. See Colors.
F18A — a second, hidden feature set inside the Pico9918: two tile layers, hardware scrolling, 64 programmable colors, flipping sprites, a bitmap layer and a small processor of its own. Locked at power-on, and available on hardware only. See F18A mode.
GPIO — general-purpose input and output, the sixteen pins of the 65C22 VIA. The joysticks and the keyboard use them; so can you.
immediate mode — typing a line without a number in front, so it runs right away. Compare program mode. See Typing it in.
jump table — the first 256 bytes of the Kernal, a fixed list of three-byte jumps. Calling one of those addresses is how a program asks the machine to do something, and the addresses do not change between ROM versions. See The Kernal.
Kernal — the ROM routines that drive the hardware: printing, reading keys, files, sound, the clock. Spelled with an a, following Commodore's original typo. See The Kernal.
KIM — a 1976 single-board computer, and here the three-board add-on that turns an ACE into one: a hex keypad, a two-line display, and a monitor ROM.
Monitor — the machine-code monitor in ROM, reached with BRK or by pressing Esc at boot. Lets you look at memory, disassemble it, change it and run it. Its prompt is a period. See The Monitor.
null modem — a serial cable or adapter that crosses transmit and receive. The ACE and a PC are both wired as terminals, so reaching one from the other needs one. See Connectors.
NVRAM — 256 bytes inside the clock chip, kept alive by its battery. The one place a program can leave something behind with the power off.
Pico9918 — the video chip. A Raspberry Pi Pico behaving as a TMS9918A, the 1979 part from the ColecoVision and the MSX, with a VGA socket on it. It also carries the F18A feature set, switched off until a program unlocks it.
program mode — typing a line with a number in front, so it is stored rather than run. RUN runs what is stored. Compare immediate mode.
prompt — the OK and the blinking cursor: the machine telling you it is your turn.
PRG — a program file with a two-byte load address on the front. What SAVE writes and LOAD reads.
slot — one of the eight 1 KB windows between $8000 and $9FFF, one per piece of hardware. The machine works out at power-on which ones answer. See What's fitted.
token — the single byte BASIC stores in place of a keyword. FOR is one byte in memory and three characters on the screen, which is why LIST has to translate. See What BASIC does with your memory.
VIA — Versatile Interface Adapter, the 65C22. Two 8-bit ports and two timers. Runs the keyboard and the joysticks here.
warm start — pressing the reset button. The processor restarts but memory is untouched, so your program and variables survive. This is the safe way out of a program that has run away. Compare cold start.
Wozmon — Steve Wozniak's monitor from the Apple I, 250 bytes long, kept at $FF00 as an easter egg. SYS 65280 from BASIC, J FF00 from the Monitor.
XModem — the file-transfer protocol the serial port speaks. LOAD and SAVE with no filename use it. See Serial and a terminal.
zero page — the first 256 bytes of memory. The processor reaches them with shorter, faster instructions, so they are valuable. The Kernal owns the first 58; the rest are yours, though not while BASIC is running. See The memory map.