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Good morning and welcome back to the ValorosoIT channel.
Do you like vintage electronic retrocomputers? You are in the right place and I invite you to subscribe to the channel and activate the notification bell!
Today's video is huge, not in terms of length, but rather in terms of content!
Content number 1: Unboxing of this Philips NMS 1520 recorder, which is the recorder for Philips MSX computers. It's good for the VG 8020, also for the VG 8010, probably who knows for any other MSX model!
2: let's write a program in Basic with the very powerful Basic of the MSX computers (which has a lot of commands, including graphics), in which the user must write the radius of a circle. Let's draw the monitor circle - therefore graphics - and then calculate the area and circumference of the circle.
3: Let's try the recorder. So: let's save the program on tape, this tape here, and reload it after turning off the computer, just to see if the recorder works.
So, how many topics we cover in a single video! If you find other channels where, in a video, you find all these topics, subscribe to them too... but don't forget to subscribe to my channel too!
Maybe we'll cut this piece, it's a bit disgusting...
Let's start connecting the Phillips VG-8020 computer to the monitor, using the cable we built in the last video, the one in which I showed how to build a video cable for Philips MSX, and let's also connect the recorder. If, then, you don't have a Philips MSX computer, you don't have an MSX in general, and you still want to try writing the program in Basic, to learn, because I like BASIC, because the idea inspires you, then you can use the emulator for Windows PCs called fMSX. You can download it, it's free, you can install it on your Windows computer and use it as if it were a normal MSX computer.
In addition to the Basic program, in fact, with fMSX you could load games, programs, other things for MSX. However, in this case, we will use it to write a program in Basic.
I had found an advert on Facebook Marketplace for this cassette recorder for the Philips MSX. I was missing a cassette recorder for MSX. I know that you can also use normal audio recorders, but I preferred to have an original one. I went away to buy it: it wasn't very far from where I live, about ten kilometers... So the trip was minimal. But I had made the short video of the trip. We open the package.
Audio cable (or data cable, in short) to connect the recorder to the computer. And the recorder with its power cable, because it is powered by 230 volts, and the manual. Let's get everything out.
So, the recorder is in excellent condition. It actually looks new. In the last video, which showed the trip, I had also tried it, in the sense that I had connected it to the power and I had seen that it turned on. However, in this video today, we actually test whether he writes and reads. If he writes and reads on tape: therefore, this beautiful 60-minute vintage TDK cassette, which we are going to insert into the recorder.
Let's make some connections:
- MSX power supply 230 volts
- MSX video cable, as I had already shown you in the last video, relating to the construction of the cable and, behind the television, composite video and audio are used
- the Philips NMS 1520 recorder connects the 230 volt AC power supply on one side (in fact we are starting to have a few wires around)
- and, lastly, you need to connect the recorder to the computer, using this audio cable, in reality the data then passes through, but it passes in audio format
We also have the manual, which explains well how to connect these wires. Not that there's any need, because there are only three. Let's see if there's a drawing... I remember seeing it the other day...
No, I was joking! There is no drawing!
However, it says: connection, the 8-pole DIN cable must be connected to the back of the MSX (this is how far we got), the white one data OUT, then the red one is the input, however, and goes to IN and the black one to Remote.
The white one, ah here it is, there's also the little white circle, you could already tell: OUT. Remote, which will therefore be turned on and off. And IN and red. Then we go to connect the data cable behind the computer.
Here, where the recorder connector is.
Nice mess of wires... and we keep it that way, unfortunately!
Shall we turn it on? Everything should work, because it is a computer that we have already tested in other videos.
Yes! Well, come on, let's write the program in Basic. As we write it, I'll comment on it. When you see the enlarged images, they are the ones I can take directly from the fMSX emulator.
10: let's put the capital letters, INPUT, then ask, you had already seen it in previous episodes of Basic, R, semicolon, R. Don't be confused: the 'R' inside the quotes is the one that is printed on the monitor, while the R outside the quotes is the variable in which the value that we will then type on the keyboard is saved.
I'm going a little fast because we had already seen it in the previous episodes of Basic.
20 SCREEN 2. This is a specific MSX command, it is used to change the graphics mode and therefore move from the text, which we see now, to a mode in which we can use the graphics commands and draw.
30: Let's draw a circle. So, with line 10 I requested the radius of the circle, with line 20 we are going to set a graphics mode, with line 30 we are going to draw a circle, which starts from the center of the monitor and will have a radius equal to what we indicated before, in line 10.
These are more or less the central coordinates of the monitor, so it is as if we pointed the compass to the center of the monitor and now we are going to say how wide this compass must be, therefore R.
Then, as you notice, there is no control on R. So, one could also indicate 1000, but, in reality, the monitor (MSX) does not have a thousand pixels, so the circle would not be drawn. At this point I can invite you, in the comments, you can write: what line can we add to the 15 for example, therefore between the 10 and the 20, which checks that the radius is actually a number greater than 0 and less than the width of the monitor, therefore, I don't know, 90, 100 pixels, at most.
Then we wait for a key to be pressed.
Um… the MSX has the special key positions a little different from other home computers.
What are we going to do in line 40? We are telling him that, if the key pressed on the keyboard, therefore INKEY$ is null, therefore I have not pressed anything on the keyboard, then it returns to line 40. That is, as long as I do not press any key, the execution of the program on line 40 remains stopped.
Now we can start this first piece of program and then we will finish it later.
Asks for the radius of the circle. Let's say, for example, 30. As you can see, the computer draws a circle, starting from the center of the monitor, with a width, with a radius of 30 (pixels).
Now, by pressing a button, he goes out.
Let's return to the program listing: LIST command. We had already seen all these Basic management commands, such as LIST, in the previous episodes of the course. What is new, now, is in fact line 20 and line 30. It also makes you understand how much more powerful the MSX BASIC is compared to, for example, the Basic of the Commodore 64. Drawing a circle with the Commodore 64 is practically, I won't say impossible, but really very complicated. Instead, drawing a circle with more advanced Basics, therefore, even the Basic version 3.5 of the Commodore 16, or the Basic version 7 of the Commodore 128, or, as you can see, with the Basic of the MSX, is really easy!
Let's continue writing the program. Let's go back to text mode, then, once I finished drawing the circle, I waited to press a key, when I press the key, it moves the program pointer to line 50 and returns to text mode. Let's do some math: well, first of all let's take and rewrite the value of R (radius). Just to summarize: so, radius R
70
Oh no, I also wanted to give it an equal, so, you see, you can use the darts to go wherever you want. We insert (INS key) and insert the equal. You see, the editor is also really very advanced.
Next, we calculate the area of the circle, which is equal to Pi * R squared. So: Pi is = 3.1415, *, where the times is, it's under the eight here, * R squared, or you can write times R * R, which is the same stuff.
80: the circumference, which we therefore call C, equals 2 * Pi * R, right?
So, in theory the program is finished, because, as we saw before, we ask for the radius, we draw the circle in graphic mode, we wait for a key to be pressed, and therefore the execution of the program remains stopped at line 40 until I press a key on the computer keyboard, subsequently, via SCREEN 0 it returns to text mode and writes to me: R = the radius of the circle that we had previously defined, A which is the area of the circle which is calculated with Pi (3.1415) * R^2 and the circumference that is equal to 2 * Pi * R.
Shall we start?
R?
Let's write 40.
He drew the circle, so it works, as we had seen before.
Now we press a key, it exits the graphics mode and writes the values.
Radius 40.
Area 5.026,4
Circumference 251.32
Well, now you could also check these values with the calculator.
Let's check the data with the calculator and then rewrite Pi. We don't use what the calculator already has inside, because we have approximated it.
3,1415 * 40^2
5,026.4 perfect! That's right!
Now let's look at the circumference, then:
2 * 3.1415 * the radius, which is 40 = 251.32 perfect!
We have arrived at the most awaited part of the video for me, which is to see if the recorder works. I put the cassette at the beginning of the black band. Do you remember how it was done?
Oh, with the BIC pen!
So that, like this, when we go to write, we find almost immediately where the magnetic stripe of the tape is and not the initial piece which is not magnetic. Let's reset the counter. We return to the program listing and save it on the cassette. So, of the various ways there are to save the program on cassette, I use the classic SAVE.
Therefore, SAVE 'CAS: to indicate that we must save on cassette, file name AMEDEO, unquote!
Now, I press SAVE and START at the same time on the recorder, which, however, remains still, because the computer has not yet pressed RETURN. Let's try?
You can hear it, it's recording, do you hear the whistle?
Already done? Very fast, very fast! So, at this point we stop, REWIND we go back with the tape and, to reload the program, we turn the computer off and on again, so we are sure that it is no longer in memory.
To load the program: LOAD 'CAS:'. There are, as I was saying, other ways to save programs in Basic, with CSAVE, CLOAD. But, actually, I also like this one, so for the moment let's use this: LOAD. We see?
Can you hear the whistle? He found it! Yessss! Let's see if the right listing is inside... And the recorder works!
So, we actually tried saving and loading a program on the same cassette, so it could also be that the recorder runs at a different speed and still saves and loads anyway. To really test the recorder, it would be nice to have an original MSX cassette and try loading a game. I don't have it, but at least the hardware is fine. At most, the alignment of the head or the speed of the engine would need to be calibrated for a moment. But I can consider myself satisfied!
Let's run the program and see if it works. This time we put R=30. Circle drawing and all the calculations, as we saw before. Perfect!
I hope you also enjoyed this video, in which we created a program in Basic, which you can also write with the fMSX emulator, if you don't have an MSX computer. We saw how powerful MSX BASIC is, because with really three lines we had already drawn a circle of any radius and with another three lines we calculated the area and circumference of this circle. Then, we tried the recorder, which works very well, we saved the program on this tape which, at this point, will remain in my archives. If you liked the video, subscribe to the channel, activate the notification bell, like the video and... write to me in the comments which line you would insert between 10 and 20 so that the program checks whether the radius of the circle is actually within the visible area of the monitor.
See you soon and the next video! Bye bye!