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27bcf5f79c
PIEWriter dot codes are case-insensitive, and I've deciphered that .pp is a paragraph break. Replace those with blank lines. The NUL at EOF was escaped, but it can be simply deleted. Did so.
328 lines
8.6 KiB
Plaintext
328 lines
8.6 KiB
Plaintext
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PAGE]>256 bytes of memory which share
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a common high order address byte.
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Zero page is the first 256 bytes of
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memory ($0000 through $00FF).
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PARALLEL]>Opposite of serial. A
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communication mode which sends all of
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the bits in a byte at once, each over
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a separate line or wire.
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PARAMETER LIST]>An area of storage
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set aside for communication between
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a calling program and a subroutine.
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The parameter list contains input and
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output variables which will be used
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by the subroutine.
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PARITY]>A scheme, similar to
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checksums but on a bit level rather
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than a byte level, which allows
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detection of errors in a single data
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byte. An extra parity bit is
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attached to each byte which is a sum
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of the bits in the byte. Parity is
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used in expensive memory to detect or
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correct single bit failures, and when
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sending data over communications
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lines to detect noise errors.
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PARSE]>The process of interpreting
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character string data, such as a
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command with keywords.
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PATCH]>A small change to the object
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code of an assembly language program.
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Also called a "zap".
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PERIPHERAL]>A device which is
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external to the computer itself, such
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as a disk drive or a printer. Also
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called an Input/Output device.
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PHYSICAL RECORD]>A collection of data
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corresponding to the smallest unit of
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storage on a peripheral device.
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For disks, a physical record
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is a sector.
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POINTER]>The address or memory
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location of a block of data or a
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single data item. The address
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"points" to the data.
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PROLOGUE]>The three bytes at the
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beginning of a disk field which
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uniquely identify it from any other
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data on the track.
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PROM]>Programmable Read Only Memory.
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PROMs are usually used on controller
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cards associated with peripherals to
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hold the driver program which
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interfaces the device to applications
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programs.
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PROMPT]>An output string which lets
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the user know that input is expected.
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A "*" is the prompt character for the
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APPLE monitor.
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PROTECTED DISK]>A diskette whose
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format or content has been modified
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to prevent its being copied. Most
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retail software today is distributed
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on protected disks to prevent theft.
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PSEUDO-OPCODE]>A special assembly
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language opcode which does not
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translate into a machine instruction.
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A pseudo-opcode instructs the
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assembler to perform some function,
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such as skipping a page in an
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assembly listing or reserving data
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space in the output object code.
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RANDOM ACCESS]>Direct access. The
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capability to rapidly access any
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single piece of data on a storage
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medium without having to sequentially
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read all of its predecessors.
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RAM]>Random Access Memory. Computer
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memory which will allow storage and
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retrieval of values by address.
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RECAL]>Recalibrate the disk arm so
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that the read/write head is
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positioned over track zero. This is
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done by pulling the arm as far as it
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will go to the outside of the
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diskette until it hits a stop,
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producing a "clacking" sound.
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RECORD]>A collection of associated
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data items or fields. One or more
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records are usually associated with a
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file. Each record might correspond
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to an employee, for example.
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REGISTER]>A named temporary storage
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location in the central processor
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itself. The 6502 has 5 registers;
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the A, X, Y, S, and P registers.
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Registers are used by an assembly
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language program to access memory and
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perform arithmetic.
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RELEASE]>A version of a distributed
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piece of software. There have been
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several releases of DOS.
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RELOCATABLE]>The attribute of
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an object module file
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which contains a machine language
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program and the information necessary
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to make it run at any memory
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location.
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RETURN CODE]>A numeric value returned
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from a subroutine, indicating the
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success or failure of the operation
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attempted. A return code of zero
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usually means there were no errors.
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Any other value indicates the nature
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of the error, as defined by the
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design of the subroutine.
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ROM]>Read Only Memory. Memory which
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has a permanent value. The APPLE
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monitor and BASIC interpreters are
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stored in ROM.
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RWTS]>Read/Write Track/Sector. A
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collection of subroutines which allow
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access to the diskette at a
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track and sector level. RWTS is
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part of DOS and may be called by
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external assembly language programs.
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SEARCH]>The process of scanning a
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track for a given sector.
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SECTOR]>The smallest updatable unit
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of data on a disk track. One sector
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on an APPLE DISK II contains 256
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data bytes.
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SECTOR ADDRESS]>A disk field which
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identifies the sector data field which
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follows in terms of its volume,
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track, and sector number.
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SECTOR DATA]>A disk field which
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contains the actual sector data in
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nibbilized form.
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SEEK]>The process of moving the disk
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arm to a given track.
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SELF-SYNC]>Also called "auto-sync"
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bytes. Special disk bytes which
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contain more than 8 bits, allowing
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synchronization of the hardware to
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byte boundaries when reading.
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SEQUENTIAL ACCESS]>A mode of data
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retreival where each byte of data is
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read in the order in which it was
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written to the disk.
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SERIAL]>As opposed to parallel. A
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communication mode which sends data
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bits one at a time over a single line
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or wire.
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SHIFT]>A logical operation which
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moves the bits of a byte either left
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or right one position, moving a 0
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into the bit at the other end.
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SLAVE DISK]>A diskette with a copy of
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DOS which is not relocatable. The
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DOS image will always be loaded into
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the same memory location, regadless
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of the size of the machine.
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SOFT ERROR]>A recoverable I/O error.
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A worn diskette might produce soft
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errors occasionally.
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SOFTWARE]>Computer programs and data
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which can be loaded into RAM memory
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and executed.
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SOURCE CODE]>A program in a form
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which is understandable to humans;
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in character form as opposed
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to internal binary machine format.
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Source assembly code must be
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processed by an assembler to
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translate it into machine or "object"
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code.
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SKEWING]>The process of interleaving
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sectors. See INTERLEAVE.
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STATE MACHINE]>A process (in software
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or hardware) which defines a
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unique target state, given an input
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state and certain conditions. A
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state machine approach is used in DOS
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to keep track of its video intercepts
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and by the hardware on the disk
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controller card to process disk data.
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STROBE]>The act of triggering an I/O
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function by momentarily referencing a
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special I/O address. Strobing $C030
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produces a click on the speaker.
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Also called "toggling".
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SUBROUTINE]>A program whose function
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is required repeatedly during
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execution, and therefore is called by
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a main program in several places.
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TABLE]>A collection of data entries,
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having similar format, residing in
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memory. Each entry might contain the
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name of a program and its address,
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for example. A "lookup" can be
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performed on such a table to locate
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any given program by name.
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TOGGLE]>The act of triggering an I/O
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function by momentarily referencing a
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special I/O address. Toggling $C030
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produces a click on the speaker.
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Also called "strobe".
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TOKENS]>A method where human
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recognizable words may be coded to
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single binary byte values for memory
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compression and faster processing.
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BASIC statements are tokenized, where
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hex codes are assigned to words like
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IF, PRINT, and END.
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TRACK]>One complete circular path of
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magnetic storage on a diskette.
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There are 35 concentric tracks on an APPLE
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diskette.
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TRANSLATE TABLE]>A table of single
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byte codes which are to replace
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input codes on a one-for-one
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basis. A translate table is used to
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convert from 6 bit codes to disk
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codes.
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T/S LIST]>Track/Sector List. A
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sector which describes the location
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of a file by listing the track and
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sector number for each of its data
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sectors in the order that they are to
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be read or written.
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TTL]>Transistor to Transistor Logic.
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A standard for the interconnection of
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integrated circuits which also
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defines the which voltages
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represent 0's and 1's.
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UTILITY]>A program which is used to
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maintain, or assist in the development
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of, other programs or disk files.
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VECTOR]>A collection of pointers or
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JMP instructions at a fixed location
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in memory which allow access to a
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relocatable program or data.
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VOLUME]>An identification for a
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diskette, disk platter, or cassette,
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containing one or more files.
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VTOC]>Volume Table Of Contents.
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Based upon the IBM OS/VS VTOC. On
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the APPLE, a sector mapping the
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free sectors on the diskette and
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giving the location of the directory.
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WARMSTART]>A restart of a program
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which retains, as much as is
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possible, the work which was in
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progress at the time. A DOS
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warmstart retains the BASIC program
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in memory.
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WRITE PROTECTED]>A diskette whose
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write protect notch is covered,
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preventing the disk drive from
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writing on it.
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ZAP]>From the IBM utility program,
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SUPERZAP. A program which allows
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updates to a disk at a byte level,
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using hexadecimal.
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ZERO PAGE]>The first 256 bytes of
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memory in a 6502 based machine. Zero
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page locations have special
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significance to the central
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processor, making their management
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and assignment critical.
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.br
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