Lntroduction; Features Of Your Disk System; Diskette Lnformation - Texas Instruments Php 1240 Bedienungsanleitung

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TEXAS INSTRUMENTS
INTRODUCTION
The Texas lnstruments Disk Memory System is a powerful combi-
nation of computer hardware and software that allows you to store
and retrieve data quickly and accurately on 5-1/4 inch diskettes
(sold separately).
The system consists of the following components:
DISK MEMORY DRIVE - The disk drive reads information from and
writes information on the diskette. lt can rapidly locate any position
or file o n the diskette as directed by the Disk Drive Controller. The
disk drive spins the diskette at a constant speed and controls the
movement of the magnetic head. You may have one of two drives
that have slightly different appearances. However, they function in
exactly the same way. Diskettes (not included) are required.
DISK DRIVE CONTROLLER - The Disk Drive Controller tells the disk
drive where to position the magnetic head in order to read or write
information properly. The controller al so puts an index on the disk,
making the data that has been written easy to locate.
DISK MANAGER GOMMANO MODULE- The Disk Manager So/id
State Software™ Command Module helps you maintain the infor-
mation on your diskettes. Naming and renaming diskettes, rena-
ming files, deleting files, copying files, and copying disketttes ali
can easy be performed with the Disk Manager module plugged in-
to the computer console.
The Texas lnstruments disk system represents a major advance
over other systems. Because the contro! software needed for the
disk system is in permanent ROM, in the Disk Manager Command
Module, and in the controller, the disk system uses a relatively
small amount of working space in the computer's available memo-
ry (RAM). The Disk Manager Command Module provides many ad-
vanced functions. For instance, in copying a diskette it rearranges
the fil es on the diskette aplhabetically. And, if you like, you can co-
PY selected files instead of an entire diskette, quickly and easily.
These and many other unique features of the disk system are
described in this manual.
Get the most from your disk system by first reading this manual
and performing the examples as you go. Al so review the appendi-
ces for special information and applications. Then use the disk sy-
stem with your own applications.
FEATURES OF YOUR SYSTEM
The most important use of the disk system is storage and retrieval
of information via TI BASIC programs. Through the proper BASIC
commands, you can:
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SAVE PROGRAMS- Each diskette holds over 720,000 bits of
information. As an example, you can sto re about 100 BASIC
programs, each 50 lines long, on a single diskette.
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STORE AND RETRIEVE DATA- You can sto re data that is accu-
mulated when your programs are run. O ne disk can hold about
90,000 characters.
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UPDA TE DATA- You ca n, through a BASIC program, update the
information in your fil es so that they contai n the latest, most ac-
curate data.
The Disk Manager Command Module canal so be used to maintain
information about the diskettes, such as the name of the diskette
and the names of the files. Using the Disk Manager module you
can:
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INITIALIZE DISKETTES- You can prepare diskettes for use by
the system. The initialisation routine provides the diskette with
header information for each sector. Each diskette must be ini-
tialised before initial use.
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PHP 1240
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NAME DISKETTES - Each diskette is given its own name, so
that the computer can verify that the pro per diskette is in piace.
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RENAME, DELETE, AND COPY FILES - These functions, of
course, can be performed via TI BASIC; however, the Disk Ma-
nager Command Module helps you quickly and easily rename
files, delete files, and make copies of files.
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MODIFY PROTECTION- You may want a file protected so that it
cannot be accidentally erased or changed. You can use the
Disk Manager Command Module to protect fil es and, when you
want to change them, to release them from protection.
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COPY DISKETTES - Diskettes and your disk system are a very
reliable storage medium. However, under certain circumstan-
ces, the data stored o n a diskette can be totally or partially lost.
For instance, if electrical power fails while the disk drive is wri-
ting o n a diskette, some datacould be lost. T o protect yourdata,
it is customary to make backup diskettes. The Disk Manager
module makes it easy lo copy diskettes for backup even if you
have only one disk drive.
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PERFORM TESTS - To ensure that the disk system is opera-
ting correctly, the Disk Manager Command Module offers two
different tests. The first checks severa! generai areas to see that
things are as they should be. The second is an exhaustive test.
At the end of the tests, ali data on the diskette may have been
removed. Before you make a destructive test, you should make
a backup copy of the diskette so that your data is not lost.
Note: Whenever a double-sided diskette is mentioned, it is wor-
king with a double-sided driver, unless otherwise stated.
Certain other Command Modules also operate with the disk sy-
stem to save and read your fil es more quickly than with cassettes
or other storage media. See the manuals for each module for fur-
ther information.
DISKETTE INFORMATION
Your disk system requires 5-1/4 inch, single-sided, single-densi-
ty, softsectored diskettes. These diskettes are constructed of a
highly flexible plastic film, coated with a thin layer of iron oxide
which can be magnetized in very small areas without affecting sur-
rounding areas. The computer interprets these areas of magneti-
zation as coded information.
Note: A diskette com es in a protective jacket, inside a storage en-
velope. For best results, keep the diskette in the storage envelope
except while using. Never remove the diskette from its protective
jacket.
Each diskette is divided into tracks, which are 40 (o n some disket-
tes only 35) concentri c circles. The tracks are numbered from
O
to
39 (or 34), starting at the outside track. Each track, in turn, is divi-
ded into nine sectors. There are thus 360 (or 315) sectors, each of
which can contai n up to 256 bytes of information, or 2048 tiny ma-
gnetized areas. The sectors are numbered
O
through 359 (or 314),
starting with sector O of the first track an d going to sector 8 o n the
Jast track. Each sector has additional space used only by the con-
troller to verify sector identification and data accuracy.
A double-sided diskette has 80 tracks (on some diskettes only
70).The tracks are numbered O to 39 (or 34) on one side, starting
with the outer track, and 40 to 79 (or 68) on the other side, starting
with the innertrack. Each track is divided into nine sectors giving a
double-sided diskette 720 (or 630) sectors. Each sector can con-
tain up to 256 bytes of information, or 4096 tiny magnetized areas.