Commodore History Part 3 - The Commodore 64

I want to take you back to the year 1980. 3 years earlier, several personal computers had made their thanks to the market like the Apple II, TRS-80, and Commodore PET. And while these computers were considered very affordable for the time, They were still out of reach for tons of individuals. By 1979, some cheaper options began to point out up like the Texas Instruments TI99 / 4, and therefore the Atari 400, both of those costing around $ 550 at the time.

Now, while these newer computers were cheaper, they were also better because that they had added considerably more advanced graphics and sound capabilities. These computers were capable of quite just being computers, they might wow their customers with fancy video games.

And while these computers were cheaper than ever before, another computer was close to enter the market which might really bring the value down. If you thought I used to be close to say the Commodore VIC-20, that was an honest guess. But that This was designed by a corporation within the UK called Science of Cambridge, but they later change its name to Sinclair Research. 

There was literally one design goal for this computer, that it might be cheap. That's this computer's distinguishing feature and each design decision made about this computer would be about cheapness. The ZX80 would lower the bar even more on affordability, starting out at 79 pounds for a do-it-yourself kit, or around 100 pounds for a pre-assembled unit.

That would be almost like $ 140 US dollars at the time. As you'll see, that's an honest bit cheaper than even the Atari or TI. And to place this money into perspective, in today's money that meant the ZX-80 cost around $ 455 US dollars, which suggests you'll buy a Nintendo Switch or a PlayStation 4 for fewer money today. But what did you get for your money?

All right, what we've here is that the Sinclair ZX80. Now, while this machine was designed and sold primarily within the uk, they might output PAL video and thus not be compatible with North American televisions.

However, this particular unit here, you'll notice that it says model ZX80 USA. So, this is often a reasonably rare machine, there weren't that a lot of of those that were sold within the USA, but this one actually does output NTSC video. Alright, so let's mention a number of the value cutting measures just within the external design of this thing. For one thing, you'll see that it's just a shell, two pieces of plastic. One piece on top, and And you'll also see that it's really small. And size, you recognize the smaller it's, the cheaper it's getting to be to manufacture the plastic. Now, this seems like it might be a ventilation here, but it's actually There's no actual holes to permit any ventilation to travel out. On the rear, these are the sole ports on the whole computer.

I mean, there's no ports anywhere else. All you've got back here may be a video output port. Now this is often an RF modulated port so it's not composite video, you really need to hook this into the antenna jack of your TV And here you'll notice you've got 3 identical looking jacks. One among them is 9 members DC in. This is often the facility port. And these two are for a tape machine. And altogether | one amongst | one in every of "> one among the really annoying things about this is often that they are doing use the precise same in all of those. So, it's possible, you know, for you to stay the facility connector into the incorrect port and theoretically fry something.

OK, let's take this thing apart and see what makes it tick. So as to require it apart there are these seven little fasteners. And therefore the way these work is you only need something to push these little posts out, like this. Then you Another thing I'd wish to means will remove the entire thing. I'm guessing these were cheaper than metal screws. Now we will lift the highest off, and as you'll see there isn't an entire lot happening here.

And also if you check out the within of the highest cover you'll see what seems like an RF shield. And also if you check out the within of the highest cover you'll see what seems like an RF shield. It's actually not. It's actually painted on conductive material used as an RF shield. Very interesting. Actually the simplicity of this machine is amazing. The keyboard is nearly a part of the most PCB. The traces on the PCB definitely appear as if they were hand drawn, and not computer designed. So, let me offer you a touch overview of how this thing works.

The most important chip here is that this big one, and it's a Z-80 microprocessor clocked at 3.25 Mhz. That speed is presumably picked for a selected reason, which I'll discuss during a minute. These two chips here are static RAM chips And over here there's one 4K ROM chip that holds everything including the list, BASIC, all of the input / output routines, etc. All of the remainder of those chips are just standard TTL logic chips ..

So, if you ’re thinking, well, gee! Where ’s the audio and video chips?

Well, I can answer the audio easily enough. There ’s not any. This computer has no audio whatsoever. Not even a beep. It ’s totally silent. OK, well, what about video?

Well, technically it doesn't have one among those either. The video itself actually comes out of this chip here, which is simply a typical off-the-shelf register. So, it can only produce 8 pixels before being fed more data. And where does that data come from?

If you guessed the CPU, you guessed correctly. The CPU speed of three .25 Mhz was probably picked to assist the CPU be in sync with a composite display screen. In fact, this technique is so cheap they didn't even use a quartz Well, let's plug this thing in. I'll need an actual television because I'll need to use the antenna jack and tune the TV to channel 2. there's no power turn on the pc. Remember, I said it had been designed to be as cheap as possible. So, as soon as you plug it in, it comes on. Or rather it's alleged to. I feel the facility port on mine could be a touch oxidized. There it goes.

OK, in order that annoying noise is coming from the speaker within the TV. But since this computer has no actual audio, I'd also just turn the quantity right down to zero.

OK, I'm getting to plow ahead and check out typing during a small basic program. You'll notice there are literally different BASIC commands printed above the keys. So you don't actually type out the essential command. So, you'll see the word PRINT is true above the letter O. So, I'm just getting to push O. Then you'll see the whole command just appears on the screen. 

Now I'll attempt to keep typing out my program. Even have to mention this is often the worst keyboard within the entire history of computers. Not only because it's a membrane keyboard, but because the layout of all of the keys is particularly irritating also. By the way, if you retain thinking the screen is shutting off once IA character, you aren't imaging it. The CPU during this computer can either run software, or update the screen.

But it can't do both at an equivalent time. Therefore why most computers had a fanatical video chip. Once you finish a line, it'll send it to the highest of the screen. You're always typing on rock bottom of the And there's a surprising reason for this. So here's my program. Now, you would possibly think the screen is really scrolling here, but the program has actually stopped with a mistake code. Unlike other computers, the ZX80 only displays a numerical error code. the primary number of the code is that the error type, and therefore the second number is that the line number that it occurred on. The rationale for this is often the ROM wasn't large enough to contain actual error messages that would be printed on the screen. Anyway, so what does error code 5 mean?

Well, let's take a glance at the manual. Believe it or not, error code 5 means “no more room on screen.” And that's why my program ended with a mistake code. You see, The ZX80 doesn't scroll the screen like other computers. If it did, then what would happen is that the program would continue running and thus the screen would stay black and you've never be ready to see what was happening due to the way the CPU can't display the screen when a program is running. But, if you think that that's irritating, you haven't seen the worst of it yet. The text screen is 32 characters wide by 24 characters tall.

That's not terribly bad by the standards of 1980. It's better than the VIC-20, and about an equivalent as Radio Shack's color-computer. But, here's the important problem. Meaning a full screen of text will use 768 bytes of RAM. I would like you to believe that for a flash, because if you remember once we were taking about the computer, it only has 1K of RAM total. So, literally, if you check out the system RAM, you'll find that 3 quarters of the RAM is employed by screen RAM, leaving only 256 bytes of RAM to write down code with. It's actually probably even worse than this because the OS probably uses a minimum of a touch RAM for itself.

However, the OS is extremely clever. Once you re-evaluate 256 bytes, which isn't hard to try to to. One screen filled with BASIC commands will usually roll in the hay, your program will start to poke into memory. It's actually designed to try to to this, so what happens is that the screen will start to fiddle rock bottom up. Therefore the more you type, the smaller it'll get. This will be particularly irritating when trying to scroll through and edit a program because It can get to the purpose you simply have a couple of visible lines to figure with. Eventually you'll find yourself with just 1 line and it won't allow you to go any longer. 

The sole thanks to store programs on your ZX80 was by connecting a recorder, which in fact was fairly standard on home computers at the time. But there have been never the other storage mediums for it, and albeit it had a cartridge slot of sorts on the rear, this was never used for game cartridges . Oh, and one interesting observation about this port, by the way. Notice that the port may be a card-edge. This is often exactly opposite of how most home computers were, where the cartridge itself would have the card-edge, and therefore the computer or computer game console would have the feminine connector.

However, this one does have some significant differences. I'll start by taking it apart, and already you'll see that it uses real, metal screws. Upon seeing the motherboard, it's noticeably smaller also. And when watching the opposite side, You'll notice it only has 5 chips. Let's do a side-by-side comparison of the 2 boards. They both use an equivalent Z80 processor. They both have a ROM chip, although the new system has an 8K ROM rather than 4K . 

They both have a measly 1K of RAM. But, what it's this chip called a ULA?

Well, believe it or not, they need essentially consolidated all of those other logic chips into one custom chip to further reduce cost. So, while the ZX80 was made up of more or less off-the-shelf parts, the ZX81 finally features a custom chip.

These computers are almost an equivalent computer, but let me summarize the most differences between them. Obviously, the chip count is smaller on the 81, but also the worth. That's right the ZX81 sold for 49 pounds within the UK, and under 100 dollars within the USA. The 81 features a larger ROM. The most changes are to BASIC. The first BASIC could only handle integer math, the new BASIC does floating point and a few primitive graphics, which I'll mention shortly.

Another big improvement was something called SLOW mode. Now, you would possibly think SLOW mode seems like an obstacle over something that's fast, right?

At least within the world of computers. Well, with SLOW mode, the ZX81 can finally do two things directly. It can generate video, while also executing program code. How does it do this?

Well, if you check out a screen on a CRT, as you recognize this screen is drawn one pixel at a time from the highest left, to rock bottom right. 

Well, during the time it's drawing the border at the highest and bottom of the screen, the CPU isn't really needed much. So, the CPU can execute other code during this era. So, in FAST mode, the CPU either devotes all of its time to program execution, or all of its time to drawing the screen In SLOW mode, the CPU will multitask and about 70% of its time is spent drawing the screen and what remains is left for executing other things. And while it does slow things down, during regular usage this is often actually preferred because a minimum of the screen doesn't flicker off whenever you press something on the keyboard.

Sinclair also offered previous owners of the ZX80 an upgrade path. Since the computers were more or less identical in function, ZX80 owners could swap out their ROM chip with the newer one, plus alittle hardware modification to permit slow mode, and that they would even receive a replacement keypad that had all of the new features printed computers. This upgrade cost about 20% of what it might have cost to only buy the new ZX81, in order that was a good strategy. The ZX81 was also destined to form more of Introducing the Timex Sinclair 1000. 

The primary of a replacement generation of computers designed to be easier to use and to have. For 99.95. Power to find out. Timex, yes that's the watch company we all know, collaborated with Sinclair Research to plug the pc within the USA because the Timex Sinclair 1000. On the rear of the box it says it utilizes FOUR powerful microc hips, including a singular master chip that replaces as many as 18 chips on other personal computers.

That's interesting because the ZX81 had 5 chips. It also states that it comes with 2K of RAM. Still not much, but it's twice the maximum amount because the ZX81. Timex also sold a 16K RAM module, and a small little Timex Personal Printer. So, let's open it up and see what's inside. Even the froth has the Timex logo. It's pretty obvious my box is missing a couple of things. But it does a minimum of have the user manual. And this manual isn't bad. It's not nearly as good because the VIC-20 manual, but it's certainly decent. Let's compare it with the ZX81. Aside from the brand, they appear identical. But there are another minor differences. For one thing, on the keyboard they changed a number of British terms.

For example, we've Rubout here, and therefore the American version says delete. On the side, you'll notice the RF video output is during a slightly different place. But, they are doing have an equivalent expansion port. Ok, let's While 2K of RAM is certainly an improvement, this module will give us 16K of RAM. And that's enough RAM to truly be useful, especially considering this computer has no graphics modes, so there's no got to store graphics anywhere, or sound, or any kind of DOS for controlling disk drives. 

So, all of the 16K is out there to be used. Of course, it does have the feminine edge connector like I discussed earlier. And, so it attaches like this. This one is pretty tight, which is sweet. I even have had them quite loose before, which is bad because Sometimes just touching the pc would make it lock up thanks to the poor connection. Timex also marketed a couple of cassette based applications, which were typically sold wherever the pc was sold.

I have no idea what that's. But one thing I wanted to say is that some games, like this one say they work on 2K of RAM. Same with money analyzer. But notice this one says it needs 16K. And another. This is often Somewhat unusual for the age because typically RAM expansion units in other computers were rarely supported by software, so this tends to suggest the RAM upgrade was pretty popular for this computer. 

Albeit there was really no commercial marketplace for games on this technique, there have been quite a few home-brew games developed. Most games were found in computer magazines. Some were type in listings printed within the magazines, where some were simply mail-order ads where you'd send off to urge a cassette mailed to you. None of those games are likely to impress a significant gamer.

However, I do find a number of them impressive just considering the system they were made for. Officially speaking, the Sinclair units haven't any graphics modes in the least. They are doing contain a personality set with several pre-defined graphics characters, By using these you'll create pseudo graphics. And albeit it did have a graphics mode, there isn't enough RAM to store any graphics on the bottom models.

However, since the graphics are software generated, with a 16K RAM expansion and a few minor modifications, you'll actually do custom hi-res graphics, like a number of these games. There weren't very many who took advantage of this type There also are some demos that make use of it. There have been also a spread of methods to urge sound out of the pc, like using the cassette port to get some simple beeps, and even going thus far on integrate sound generator chips from other platforms, however, little or no software takes advantage of that either.

Another popular upgrade modification was within the sort of aftermarket cases and keyboards which, when combined with a RAM upgrade could make these computers almost functional and tolerable computers to figure on. The Timex unit was at one point selling for as little as $ 49. One funny situation this created is that Commodore had been running an ad campaign claiming to offer people a $ 100 credit for the trade of any computer or game system. 

So, many of us realized they might buy the Sinclair unit for 50 bucks, then trade it certain a $ 100 credit on a Commodore. Of course, a few of years later, Timex came out with the Sinclair 1500. This version comes standard with 16K of RAM and a way better keyboard. Here we go. It's all an equivalent ports on the rear. But one thing I notice directly is that it's substantially heavier, which may be a good thing compared to the previous units. Now, the keys are Chiclet keys, which are typically hated within the industry.

However, compared to the membrane keyboard these are like heaven to type on. I assume everything is relative. The user manual for the 1500 is additionally pretty nice. Let's have a glance inside. It's a touch more advanced, and clearly it's 8 RAM chips The ULA is now during a square package rather than a DIP. But the general architecture is nearly just like previous versions. The 1500 was ultimately a market failure, despite the very fact that it had been sold for round the same price as its predecessor , only it's actually a usable, functional computer that you simply could actually like do stuff with. 

The matter was the competition was fierce by 1983 particularly from products like the Commodore VIC-20, but also from Sinclair's own new product called the Sinclair Spectrum, Which we'll mention in another episode. The Sinclair ZX81 are often seen in some TV shows like the IT Crowd, where it's even mentioned a couple of times. And while not actually shown, it's mentioned on red dwarf st ar.

I think the Sinclair systems were quite important from a perspective of getting the value of computing down. But, to match them with cars, for a flash. Buying a ZX81 was kind of like buying one among those motorized shopping carts that you simply see in Wal-Mart and claiming you purchased a car. Where, buying a VIC-20 at the time was kind of like buying a Nissan Versa or a Chevy Spark. I mean, sure, they're cheap but a minimum of they're a true car. 

Then we're almost done talking about the Sinclair systems yet because we've to hide the Sinclair Spectrum, which was a much more iconic computer, I think, particularly within the UK and we'll get thereto during a later episode But, as far as these systems go, they're historically important for being the butt of computer jokes for one thing, but beyond that they are doing deserve special recognition for bringing the value of computing down.

And only for their sheer simplicity. I mean, a number of the planning decisions they made in these computers, while yes, they ultimately made the computers less usable, a number of them were brilliant, as far as the way to get the value down And so, they are doing deserve recognition for that. And, in order that about wraps it up for this episode, so as always, thanks for watching and stick around for subsequent one.

Compaq Portable Restoration (Part Two)