The story goes on - Amiga 500

  I had pleasure to use turbo system on the little Atari only for about six months, and fortunately I didn't have to suffer from all those tape related problems too long. Soon, in early 1991 my Dad has bought me an Amiga 500. As a matter of fact we had to sacrifice the little Atari (just to get enough money), but it was well worth it. Amiga had brilliant specs:

• CPU: 16-bit Motorola MC68000, with 7.09 MHz clock
• memory: 512 KB RAM!!! which later we expanded to 1 MB
• wonderful sound: 4 × 8-bit channels (digital sound!) at max 28 kHz with 6-bit volume in stereo
• text: 80 columns x 32 lines
• unbelievable graphics: 640 × 512 resolution or 640 × 256 in maximum 16 colours, 320 x 256 or 320 x 512 in up to 32 colours, or 64 colours in EHB mode and even 4096 colours in HAM mode. However displaying in vertical resolution of 512 was in interlace mode

  For those who don't have a clue what interlace is, it is a way of getting twice higher vertical resolution from the Amiga's custom chipset. But it came at a cost. Instead of scanning the whole screen at once, all the odd scanlines were "drawn" first, then all the even ones. That caused a horrible flickering effect and screens were usually far too shaky to be usable on a TV or even a monitor. To eliminate that effect completely so called Flicker Fixer needed to be used.

EHB (Extra Half-Brite) uses six bitplanes, or in other words six bits per pixel. The first five bitplanes index 32 colours selected from the full 4096 palette, and the sixth bitplane  causes display hardware to half the brightness of the corresponding colour component. Thus EHB allows 32 colours out of 4096 plus their half-bright counterparts.

  HAM (Hold-And-Modify) uses a very unusual technique to code the colour of pixels, allowing many more colours to appear on screen than would otherwise be possible. Yet, it has significant technical limitations and therefore cannot be used as a general purpose display mode. It could be used for the display and manipulation of static images. This is how it works: pixels are represented using 6 bits each; 2 bits are used as decision-making "control" bits, and 4 bits are used as "data" bits. The actual colour for a pixel would be the result of following the instruction of the control bits. The 2 control bits allow for four possibilities, which are as follows:

• Set: Use the 4 bits of data as an index into the first 16 colors in the color palette. Use that color for this pixel
• Modify Red: Hold the green and blue color components of the previous pixel. Use the 4 bits of data as the new red color component of this pixel
• Modify Green: Hold the red and blue color components of the previous pixel. Use the 4 bits of data as the new green color component of this pixel
• Modify Blue: Hold the red and green color components of the previous pixel. Use the 4 bits of data as the new blue color component of this pixel

HAM6 graphics mode

A parrot in HAM6 mode

  Now it is clear why HAM mode couldn't be used for things like games or animation. The same trick that makes it possible to display all 4096 colours at a time, also doesn't allow to instantly change neighbouring pixels from one colour to another, and may cause "smudges" on the edges of objects. One can see it in the image above, the picture simply isn't very sharp. Fortunately, it was perfectly sharp in all other modes. So, let's have a look at this great "computing machine":

Amiga 500 with a colour monitor and external floppy drive 

  I possessed (and still do) a slightly different configuration, with a TV instead of a proper computer monitor, TV modulator and a slim external floppy disk drive (which I acquired some time after buying the computer for money I made collecting mushrooms in local forest; another great, ecological and profitable activity). I've had the TV screen (for which cable I made on my own) for about 20 years already and it still works, although the picture it displays isn't great. And it's monochromatic. I guess I'm going to replace it with some small LCD TV at some point (colour !!!). Until today I've kept the original box in which came my first Amiga 500.

My Amiga 500 original box

  The computer itself still works and is placed in the same location I used it 20 years ago.

My good old Amiga 500

  As you can see that computer was armed with a 3.5" floppy drive (built-in) and I loved it from the first sight. For those who have never encountered one, I have pictures of both sides of a 3.5" floppy disk (my great game "Robot-R29 is on this particular one). Those used in Amiga had a 880 KB capacity, and back then I thought it was a lot. However some newer models, starting with later models of Amiga 3000 were fitted with the 1.76Mb Hi-Density disk (special Hi-Density floppies needed to be used).

Double-Density 3.5" floppy disk (top side)

Double-Density 3.5" floppy disk (bottom side)

  I mentioned TV modulator. Yes, Amiga 500 didn't feature that interface, and if one wanted to connect their computer to a regular TV through an antenna port (I guess most people did) they needed to purchase a TV modulator. That could be also done through the composite video output, however this model of Amiga generated only black & white signal through that output, which was rather impractical if one wanted to play and enjoy games with beautiful colour graphics. Therefore people spent money on that adapter, which was rather a bulky thing stinking out in the back of the computer, with two audio leads connected to stereo output and one input in the modulator. Yes, it turned the stereo signal into a dull mono. But it was an acceptable trade-off if one didn't have enough money to buy a proper monitor.

TV modulator...

...and a box it came in

  My computer came with a mouse, too. And as a matter of fact, it was the very first mouse I have ever touched in my life (at least a computer one). Also, it wasn't optical mouse like all those we see nowadays. It was a proper old school mechanical mouse, which you can in the second picture below. It's that little thing slightly sticking out from the little hole in the bottom of the mouse (sounds a little funny, that computer science is all fun, I'm telling you). That type of mouse was little harder to work with, and more demanding in terms on the surface (it couldn't be too smooth) on which it was used than present days mice, but at those times it was what everyone had.

Top side of my mouse which still works after so many years

And its bottom side (notice ball in the whole on the right)

  But mouse wasn't just an optional gadget like it could've been in case of the little Atari. It was a necessary device used to interact with GUI (graphical user interface), and that was completely new to me! Before that I might have seen a computer with GUI on the TV, but I don't recall I had encountered it. The first time I had a go at GUI on Amiga I was blown away. The difference between obsolete editor and direct mode on Atari XE where everything had to be typed in, and GUI on Amiga (which was called Workbench by the way) was so huge it could never be forgotten. Although in a way Amiga also had a similar feature, called CLI (command- line interface) in which user also typed in commands in order to perform disk operations, it was rather for advanced users and wasn't vital to be able to use computer. As you can see, everything was represented in form of little pictures (yes, they're called icons) which user could point with the mouse cursor and simply click it to make something happen. That simple!

The main window of Workbench 1.3 (the orange bar in the right part of the windows shows disk usage)

Some example applications open in Workbench 1.0 (main screen worked in 4 colours in 640x256 pixels by default)

  Mouse wasn't the only controller for the Amiga. The computer also was a great game platform with countless number of different titles released over its lifespan. Therefore pretty much every Amiga user had at least one joystick. I was no different, although I didn't play games too often. Rather my younger sisters enjoyed that kind of computer entertainment. One of these joysticks (the one on the right) is older than my Amiga. I actually started using it with my Atari, some time before I even got my Amiga. Joysticks were a sort of ancestors of nowadays game controllers.

Amiga joysticks

  Amiga Workbench itself came on a floppy disk, plus another disk in the set:

• Workbench 1.3 Disk containing programs like Calculator, Clock, Notepad, Say, Prefs (system preferences) and CLI
• Extras Disk with Amiga Basic, but also some tools: Fed (bitmap font editor), IconEd (icon editor), Palette allowing to change colours in Workbench, and Terminal which could be used to connect to other computers

My copies of Amiga Workbench didn't happen to be original, but I still posses them

  As you can see the Amiga was quite capable computer for the early 90s and Amiga 500 was actually computer that was first released in 1987. Soon after I got my first Amiga another model was released in 1992, it was Amiga 1200 which had lot better graphics and of course it was faster, although sound capabilities remained pretty much unchanged. Nonetheless, both Amiga's graphics and sound were pretty impressive at that time and actually no other computer at that price tag could boast it. For that reason most Amiga users had these two programs: Deluxe Paint (bitmap graphics editor) and ProTracker (music tracker).

Deluxe Paint

ProTracker

  As you can see it was a huge progress and a great upgrade from the little 8-bit Atari. First of all Amiga was a 16-bit computer which combined with the faster clock to the user meant much more speed as the result. 16-but technology also allowed to address much more memory. Superb graphics and digital sound were extremely impressive for that time, too. All that combined with Amiga's GUI based operating system made it first choice for several people in the late 80s and early 90s. To me it will always be a wonderful unforgotten experience.