Loading your programmes.
Before we tell you how to LOAD your program in order to keep it for
further use at any time, well explain the way in which it is kept and used
in Random Access Memory-or RAM as it is more frequently called.
All information entered into the computer either by you using the
keyboard or from acassette tape (or adisc) is held in the form of
BINARY NUMBERS. These numbers are represented by either ONES
or ZEROS.
The computer does this by turning on or off literally tens of thousands
of electrical switches known as TRANSISTORS which are inside
INTEGRATED CIRCUITS or MICRO CHIPS.
The BINARY CODE is something like Morse Code-which has
combinations of dots and dashes to represent letters of the alphabet;
numbers as well.
With your computer, once the power is turned off all the switches revert
to zeros and your program is lost forever! If we want to keep aperm-
anent record of the program, it must be transferred to cassette tape.
When you have completed aprogram on your John Sands Sega and
wish to keep it, you use the SAVE command. When this occurs, the
computer converts the BINARY CODE into audible sound tones which
range from frequencies of around 3000 Hertz (or cycles per second)
which represent the zeros, and around 5000 Hertz which represent
the ones.
On atypical SAVE command, aconstant ‘leader’ tone of 4seconds is
heard, followed by aburst of File Header Data which contains the File
Name, followed by another 4seconds of constant tone. This is then
followed by the program code being SAVED in bursts of 600 bits
per second.
You can hearlhese sounds occurring over the cassette recorder
loudspeaker if you disconnect the earphone jack.
If we wish to reload the program into the Sega from the cassette tape,
we use the BASIC command LOAD. The computer will then search
over the tape for the leader tone. When it finds the File Name you
require, it will announce the fact on the screen by printing the words
FOUND FILE (NAME). It then continues to LOAD the program code for
up to several minutes. When it has completed the job, the words
LOADING END will appear on your screen.
The program is now in the computer's Random Access Memory (RAM).
The tape can be stopped, and by pressing the RUN key you will start
the program.
If your Sega cannot find the leader tone, or the particular File Name, it
will keep on looking forever! During the LOAD or SAVE activities, there
wil! be no response from any of the keys on the keyboard, except for
RESET
!f you know your program is near the beginning of the tape, you should
have aFOUND FILE (NAME) response in about 20 seconds. If this
doesn’t happen we suggest you rewind the tape and try again; this
time starting with the volume setting at the mid point and gently
increasing it. Hopefully, you will hear something!
When the computer does find the leader tone it will then attempt to
LOAD. At any time during the LOAD process, you may see aTAPE
READ ERROR appear on the screen. This means the computer has lost
the signal which is coming from the tape and the LOAD operation has
been discontinued.
There are several causes of this infuriating problem! So it’s best to make
sure they never, or hardly ever, occur.
The most common are these;
Poor quality tape. Always use Low Noise 60 minute, or shorter tapes.
Never use Chrome or Metal tapes.
Kinks in the tape. Never leave the Play button on when you’re not
recording.
Poor quality original recording. Make sure you verify all your SAVES.
Make aback-up tape of everything too.
Bad electrical connections. Make sure your leads are not faulty from
the recorder to your John Sands Sega.
Poor alignment of recorder head. This can result in signal loss which is
definitely what you don’t want! Make sure you use awell-known and
reliable recorder.
Signal recorded too low. Adjust the VU recording level on your cassette
deck to give the maximum signal power without distortion.
From all the above, you can see that to SAVE and LOAD computer
programs is quite acritical process. More so, than for voice or music
recording. Asmall loss of signal might not be even noticeable by the
human ear- but It’s absolutely vital for your Sega. You cannot load just
part of aprogram either; it’s all or nothing!
It’s afunny thing, but some sophisticated hi-fi cassette decks do not
make as reliable computer recorder units as less expensive, portable
models. This is because the costly units very faithfully reproduce high
frequency sounds as well as any other noise which may be on the
tape. All this does is to corrupt your data signal and the result is not the
one you’re looking for!
The best of all cassette data units are those which have been produced
especially for use with computers. These are called 'dedicated' models,
and contain special filters which restrict the recorded signals to the
frequencies we want.
You can also expect potential problems if you SAVE aprogram on
one recorder and LOAD it from another. Nearly all mass produced
cassette recorders have slightly different head alignment and signal
characteristics.
If you SAVE a program using aparticular recorder, we suggest you use
the same recorder to LOAD the program wherever possible.
The equipment you will need.
You’ll need arecorder compatible with your John Sands Sega. If you
already own aportable or hi-fi cassette recorder, try it out anyway.
Then you’ll need at least one connection cable with standard 3.5 mm
Earphone Jack on both ends-or an RCA jack on the recorder end if
you are using ahi-fi deck.
And, naturally, agood quality blank audio cassette tape.
Once you've got that list organised, you’re on your way!
How to save your programs.
1.Connect the cable from the OUT socket on the back of your John
Sands Sega to the MIC or MICROPHONE socket of your recorder.
2. Advance the tape until the brown, magnetic section is visible on
both reels.
Hold down the FUNC key and press the SAVE key on your Sega.
The screen will indicate SAVE.
Now type aFile Name-which can be up to 16 characters long.
3. Press the Record and Play keys of your cassette recorder; then
press the CR key on your Sega.
On the screen you will now see SAVING START
This means that your data is now being written to the tape, and can
take from one to several minutes, depending on the length and
complexity of your program.
When the SAVE is completed you will hear aBEEP and the screen
message will change to SAVING, END.
4. Now we’re going to check that all the information has been SAVED
on the tape.
Rewind the tape.
Connect the cable from the Earphone or External Speaker socket of
the recorder to the cassette IN socket on your Sega. Adjust the volume
level of the recorder to %of its maximum.
5. Hold down the FUNC key of the Sega and at the same time press the
VERIFY key.
The screen will indicate VERIFY.
Now type in your File Name and press the CR key.
The screen will then showVERIFYING START
Now press Play on the recorder.
Within 20 seconds you should hear aBEEP and the screen will read
FOUND FILE (NAME).
