Buzz Words
                                        BY: Brian Heyboer (Q-Link ID: MOSFET)

FROM: HUNTSVILLE ALABAMA COMMODORE
      KOMPUTER SOCIETY (H.A.C.K.S.)
      NEWSLETTER.

In this edition of Buzz Words, I will discuss terms associated with Disk
Drives.  This is not intended to be a tutorial on the use of disks and disk
drives, but rather a dictionary and aid in reading other literature about
these subjects.

Disk Drive - A recording device which magnetically records on disks.

Floppy Disk (aka Floppy, just Disk, or sometimes Disc) - A disk-shaped piece
of magnetic recording media (the same type used for recording tape) in a
protective jacket.  They come in a variety of sizes,such as 8", 5 1/4" and 3
1/2".

Diskette - a 5 1/4 inch floppy disk.

Disk Density - A rating system for disks showing the amount of data which may
be reliably recorded on the disk.  Commodore 1541 and 1571 drives are Single
Density devices, but Double density disks may also be used (and are
recommended by Commodore) but the added density does not allow you to put more
data on them.  Many Quad density disks (those labeled High Density or "for
PC-AT") CANNOT be used with Commodore drives, as the recording media is
manufactured differently.

Double Sided disk - A disk which is rated for recording on both sides (when
used with a Double-Sided drive such as the 1571).  The 1541 is single sided,
but double sided disks may also be used (but you won't normally get more
information on them -- see Notching below).

Soft Sectored disk - A disk which does not have physical separations (holes in
the disk) between sectors.

Hard Sectored Disk - A disk which does have physical separations between
sectors.  [NOTE:  Commodore drives can use hard or soft sectored disks.]

Write Enable Notch - A notch in the side of a disk which enables the drive to
record on it.

Write Protect Tab (or just Write Protect) - An adhesive tab which covers the
write enable notch and disables recording on a disk.

Notching - The process of creating a write enable notch on the opposite side
of a disk in order to enable writing on the back side of a disk with a
single-sided drive by flipping it over.

Disk Operating System (DOS) - That portion of a computer's internal
programming which controls access to the disk drive.  In Commodore machines,
this is inside the disk drive unit.  [NOTE:  Some computer manufacturers use
the term DOS to describe an entire operating system which is DISK BASED.]

Wedge - Any one of a number of "DOS Manager" programs (especially the
Commodore DOS Manager 5.1) which make use of DOS commands easier to use.  A
wedge is a program which resides in your computer which is activated by a
special key (usually "@" or ">").

Format - A process which prepares a disk for recording of data. 
Synchronization marks, a block allocation map, and directory are placed on the
disk during this operation.

HEADER - A BASIC 3.5 command which formats a disk. [NOTE:  All references to
BASIC 3.5 indicate availability in BASIC 3.5 or Higher, including C-128 BASIC
7.0 and some BASIC extensions for the C-64.]

Directory - A file on a disk which contains the title of the disk and of the
files contained on the disk and tells the DOS where to find each file.  On
Commodore computers, the directory itself has the title "$".

CATALOG (or DIRECTORY) - A BASIC 3.5 command which causes the disk directory
to be displayed.

Block Allocation Map (BAM) - A section of a disk which designates which blocks
of the disk contain data and which blocks are free.

Block - A section (track and sector) on a disk which (on Commodore machines)
is capable of recording 256 bytes of information.

Track - A circular section of a disk that has been mapped out for data
recording.  On Commodore 1541s, there are 35 sectors per disk; on 1571s, there
are 70.

Sector - A section of a track.  On Commodore drives, the number of sectors
varies depending on the track number.

Sequential File - A data file recorded on a disk which is accesses
sequentially (from start to finish).  [Designated with "SEQ" in a directory]

Program File - A file of data which contains a program.  On Commodore
Machines, these begin with a load address and are sequential in structure. 
[Designated with PRG]

Relative File - A random-access data file.  [Designated with REL]

User File - Essentially, a sequential file with another name.  [Designated
with USR]

Splat File - An incomplete file on a disk, designated by an asterisk (the
splat) beside the file type.

SAVE - A BASIC command which creates a program file.

LOAD - A BASIC command which reads a program file and places it in computer
memory.

Scratch - The process of erasing a file.
Validate - The process of rebuilding the BAM to insure all blocks are properly
allocated and delete any splat files.

COLLECT - A BASIC 3.5 command to validate a disk.
 
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