Radio Shack TRS-80 Model II Reference Manual page 7

MODEL II TRSDOS
Disk File Requirements
There are three general configurations of diskettes that may be used in the TRSDOS
system:
• Full system - The factory release copy of TRSDOS for use in drive
o.
• Minimum system - May be used in drive 0
after initialization.
• Data - May only be used in drives
1,2
and
3.
"Full System"
This is a diskette which can be used to start (' 'bootstrap' ') the operating system and
perform all the library commands, utilities, and supervisor calls. The factory
release copy ofTRSDOS is a full system.
The full system contains many files which will not be needed for day-to-day
applications- but which may come in handy every now and then. For this reason,
you should always keep your factory release version ofTRSDOS intact, and use a
backup copy as a working master.
Why and How of Full System Diskettes
If you have a Disk Expansion Unit, you will probably find it most convenient to
have a Full System Diskette in drive 0 at all times. This will give you access to all of
the utilities and system functions without a disk swap being necessary. For most
applications, there is still plenty of room left on a full system diskette for program
storage and for small to medium sized data files. Larger data files may be stored on
data diskettes in the Disk Expansion Unit.
It is faster, by the way, to put different files or programs being accessed at the same
time on different drives since, in most cases, the drive seek time will be reduced.
On each drive, the read/write head will usually be closer to the desired location of
the file
~urrently
being accessed. Using CREATE before building the data file will
help insure that the file will be stored in a large block of contiguous storage on
diskette. This will also help speed up disk accesses.
The working master that you create will be a full system diskette. The original
master is also a full system diskette and both should be kept that way.
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