Letters to the Editor

Dear Ed,

The following is a tutorial that I gave my users’ group at our last meeting. I think it would be a good way to have your MARQUEE program run. I haven’t found any problems with this method as of yet, but Murphy says that there must be one.

LOAD & RUN PROGRAM

5 REM LOAD & RUN
7 REM TO SAVE THIS PROGRAM-
8 REM TYPE "RUN 40"(ENTER)
10 PRINT "THIS PROGRAM IS NOW
          RUNNING"
15 SCROLL
20 GOTO 10
30 STOP
40 SAVE "LOAD AND RUN"
50 RUN 5

After entering the program, RUN it to verify that is does run. BREAK the program, set up the recorder for recording and enter RUN 40. After the program has been saved, it will automatically start running.

Rewind the tape and enter LOAD””. After the program has loaded, it will automatically start running. The key to having a program start running as soon as it is loaded lies in lines 40 & 50. The commands in those lines may occur anywhere in the program as long as the program execution does not enter those lines. It is best to have a STOP command precede those lines just for safety.

If variables are to be saved and then loaded with the program, GOTO commands should be substituted for the RUN commands. To the LOAD & SAVE program, make the following changes:

5 - add "WITH SAVED VARIABLES"
8 - change RUN to GOTO
40 - add "WITH SAVED VARIABLES"
50 - change RUN to GOTO
Add line -12 PRINT A$

In the immediate mode, type “LET A$ = “THIS IS A SAVED VARIABLE STRING”

Now type “GOTO 40”, start the tape recorder and hit enter. After it has been saved, the program will start running. STOP it and enter NEW. Rewind the tape and type LOAD “” and start the tape. When the tape is loaded, you will see it running with the added message that doesn’t appear in the listing.

About the MARQUEE program – I really like it and plan to use it for a display at the next meeting.

I would like to see a tutorial on the trig functions and their use with the PLOT function.

Thank you for a great magazine.

Jim Wallace N3ADF
PG-ZUG
Prince George’s Sinclair
Users’ Group
5448 Tilden Rd.
Bladensburg, MD, 20710

* Thanks for the great tutorial, Jim. This procedure is somewhat covered on page 80 of the Sinclair manual, but like many people, I’m the type of guy that “when all else fails, read the instructions”.

As you can see, I put your hints to good use on some of this month’s programs and found them especially valuable in a menu-driven program that stores and retrieves files. I’m sure most of our readers feel the same – Ed.

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Dear Ed.

I have now take delivery of my 48K ZX SPECTRUM. After the initial euphoria, I have taken stock and consider it to be a superb machine. Using it with a small screen colour TV is really something and I can heartily recommend the purchase of one of these when they become available over there.

Much of the BASIC is, of course, directly compatible with ZX-81 BASIC but often on different keys one spends quite a while correcting typing errors caused by a long familiarity with the ZX-81 layout. One problem for me, at the moment, is machine code, particularly where ZX-81 routines call subroutines from the 8K ROM. They do not work on the SPECTRUM. So until someone more clever than I produces the disassembled 16K ROM, I shall have to stick to SPECTRUM BASIC, which is quite fast.

My greatest delight is the LOAD/SAVE/VERIFY set-up – very quick indeed, and with colour, one gets a very spectacular display while these functions are operating. A great help is the listing of programs passed through on the cassette while searching for the one you actually specified to be loaded. I have seen something similar on a large PET, but I’m not sure that if any other micros offer this feature. It is certainly a valuable one as far as I’m concerned because one can really store a very large number of SPECTRUM programs on a standard C-60 or C-90 cassette, and it is excellent for the computer to tell me the whereabouts without actually going through the motions of loading each program along the way.

A point to bear in mind, if you decide to order a SPECTRUM when it becomes available in the U.S., is that the system variables, memory maps, etc., take up approximately 6.5 K of RAM. So unless cost is a key factor, it does not seem worth-while buying a 16K version when the larger one is not all that much more expensive, compared to other micros. I remember groaning about the hungry nature of the 8K ROM as opposed to the 4K original. Little did I know what was to come with the 16K ROM !!!

I liked “MARQUEE-2” and had intended using it to write this letter; however, I decided to use a common old DEC PDP-11 (What ?? only 16K BASIC memory? – chicken feed !!!), mainly because the typing is a bit faster and easier (plus the fact, of course, that one can get more words on a line than with a ZX printer).

I intend adapting some of your programs for the SPECTRUM & will let you know how I get on and if I have been able to perform any improvements (at this stage, the latter seems unlikely !!).

Finally, I am intrigued by the signature on the drawings in SYNCHRO-SETTE. If it is not a rude question, is she the wife, mother, daughter, sister or whatever? Irrespective of the answer, it is nice to see the ladies involved. After all, ZX-ing should not be an all-male preserve, or don’t you agree?

Regards

Leslie W. Tyler
Cheltenham, England

* Actually, Marilyn is my brother. Mom and Dad had a strange sense of humor, bless ’em – Ed.