Archive for November, 2007
GW-BASIC
November 29, 2007
I first discovered this little gem while poking around on my Tandy 1000 RL computer back in 1991. Because I was familiar with various versions of BASIC already, I was able to fire it up and immediately begin writing fairly simple applications. However, there were differences to Atari’s version of BASIC, and no discernable way to figure that out without a book or some other documentation. I poked around on a few of my favourite Bulletin Board Systems (BBS) and found a small cache of programs written in GW-BASIC. I downloaded each of them, spending all of my download credits in the process. I poured over them line by line and found myself having more questions than answers.
Many new programmers today expect there to be some sort of documentation available when they learn a new technology. It’s an expectation that has evolved over the years. Today, it would be practically unheard of if you couldn’t find some resource describing the software on the Internet, or some blurb in a book, or even bundled with the product. However, when I started looking for a book on GW-BASIC (version 3.23 to be exact), it was darn near impossible. The people I spoke with had no understanding of programming, let alone a specific language. The computer sections in the store were spartan compared to the sections you find in stores today. In fact, several years later, I still needed to special order the books I wanted through the book store; even today, I usually order my titles through Amazon since a store like Indigo usually doesn’t have them in stock.
I eventually wandered into a local computer store – I was attracted by a demo of Wing Commander II playing on one of their expensive new 486 machines, so I went in to ask them if they knew where I could get my hands on some material. I spoke with the owner and he seemed to recall seeing a book for BASIC in the back of the store. He left for a couple of minutes and returned with two books under his arm. One was for the exact version of GW-BASIC I was looking for and the other was a compatible book for MS-DOS. I was ecstatic and I nearly fainted when he gave them to me for free. I don’t remember what I said to the man that day, but I’m sure it wasn’t adequate.
I wrote so many programs in that environment. I think I still have a few of them today on floppy diskette. They were simple at first, like simple word games such as hangman. However, it wasn’t long before I discovered how to increase the resolution and colour depth and draw simple graphics. I had already written code for the Atari which made use of pixel plotting routines or simple geometric shapes. There were pre-canned routines the Atari provided for drawing shapes, along with a few parameters for style, colour, and shape. GW-BASIC was similar but provided several more commands and options. With a smaller font and a higher resolution, debugging within BASIC became more feasible. I still couldn’t scroll, but at least I could view a larger portion of the code on the screen.
Sound was also possible through the PLAY command, or if you were so inclined, through a custom routine written in assembly language which could be written to generate all sorts of sounds like noise or even speech. I had converted several songs using music sheets and converted them to their GW-BASIC equivalent. Not terribly exciting, but it did make for some creative demos which seemed to impress onlookers.
Some of the more interesting projects involved controlling external devices like printers. I must have programmed my software to use every conceivable option available through my Star NX 1000 II dot-matrix printer. I could instruct it to use standard type effects like bold and italics when printing text, but I could also program it to print graphical data like images and shapes. I even created printed graphics for the Mandel Brot set by rendering the fractal to my printer instead of the screen, one pixel at a time.
Perhaps the most interesting device was a robotic arm which was controlled through a series of commands dispatched through the parallel port. I didn’t have access to such a device at home but my school eventually purchased one, so one of the teachers decided to create a contest for students. Whoever could program the robotic arm first, would win a special prize. The task was to pick up a piece of chalk and draw a picture consisting of at least four shapes. It was a fun contest and I walked away with a pass which granted me as much lab time as I wanted.
Before I upgraded to a new machine and moved to a new version of MS-DOS, I was intimately familiar with every command in that book, even the more obscure commands like CHAIN and PCOPY. Although, the really obscure commands were still a mystery. I didn’t know you could actually write assembly language routines in GW-BASIC using DEF USR and USR commands until sometime later.
Amiga OS
November 27, 2007
At around the same time I discovered DeskMate, the Amiga OS made its entry into the market as the aptly named operating system for the Amiga computer. Until recently, I had never owned an Amiga machine. I spent a fair amount of time with friends mucking around with various bits of software and hardware. One of my favourite combinations was the NewTek Video Toaster which was a powerful video editing software kit. You could do all sorts of video effects and overlays due to a technology called genlock. Genlock allowed you to synchronize different signals so that their sources become coincident, which made it possible for you to place blackout bar over your sister’s face just for kicks.It also sported several hardware and software features which I had never seen before. Real hardware multi-tasking was available on the Amiga 1000, but we mostly used the Amiga 500 which wasn’t as sophisticated in the same areas but provided terrific hardware for games. A friend of mine had a massive collection of software which were all archived in a custom-built diskette storage case made of wood and decaled with the Amiga logo. When we weren’t playing games and slogging through his massive collection of software, we were programming in Amiga BASIC or the occasional dip into the Lattice C compiler. I didn’t really understand the compiler since it was my first experience with a compiler, and it’s really difficult to learn a new programming technology when you have no means to experiment in your free time and no books available to read. At the time, I really wasn’t that interested anyway because I really connected with the structured BASIC available on the Amiga. It was a technology I could more readily understand because of my experience with Atari’s BASIC and Tandy’s GW-BASIC.
The Amiga OS made a strong impression on me as to what I was missing when I used a personal computer running DOS or Windows. There really wasn’t any comparison at the time. I remember feeling a bit underwhelmed whenever I switched my machine on after returning from a night of Amiga fun. However, after a few hours I was back into full swing. I’m not sure if I came to the realization that the machine I owned presented me with all sorts of different puzzles and tantalizing delights, but I do remember feeling like there was so much more to explore and learn. I believe that is what kept me from begging my folk’s for an Amiga every time I returned home. Although, I might have asked once or twice…
Despite Tandy’s DeskMate application which tried to handle a number of disk and application related functions, MS-DOS (Microsoft Disk Operating System) was the actual operating system on which Deskmate needed to operate. I had experience with an earlier version of Microsoft’s DOS which I used at school; I believe the versions were 2.0 and 1.25. Unlike today where hard drives are common place and often taken for granted, the machines in the lab could only boot by way of 5 1/4″ floppy diskettes which contained the operating system. I believe the Tandy computer came with MS-DOS 3.42 and it was pre-installed on the hard drive. This was so much better than booting from a floppy, and I quickly assimilated as many commands as I could, since the school never gave me the time I wanted on the machine or the resources. Even with the aid of a text book, there were a few commands which took me a while to grasp, like COMMAND.COM or DEBUG.COM. My understanding of these wouldn’t completely solidify until I started programming in lower level languages like C and assembly language. I was also introduced to Microsoft’s shell scripts which they called Batch files. With the addition of extra software on the system, these scripts could actually become fairly sophisticated. Before I moved on to greener pastures and more flexible user interfaces, my system had sophisticated menus and launchers which helped my family out when they wanted to use the machine (it wasn’t often, but it did happen).
Version 5 was a much more refined operating system and contained powerful commands and programs like QBasic. It also featured a memory manager which allowed software to access all of that wonderful new memory that you may have been fortunate enough to acquire. Although it was included in MS-DOS Version 4, I believe the DOSSHELL command’s popularity spiked in Version 5. This was a program which was intended as a graphical replacement to the dull COMMAND.COM shell. It introduced a feature called task swapping which allowed you to load more than one program but only run one of them at a time; unlike multitasking which appears to run more than one program at the same time. Also, DOSSHELL could not load more programs than your memory would allow since it did not have a paging mechanism. Naturally, all of these benefits conflicted with the new versions of Windows which did exactly the same thing only better, and was soon relegated to a supplemental disk in future releases before being dropped entirely.
Version 6 introduced the much feared DELTREE command. DELTREE was a command which could recursively remove directories and files; it was so feared because new or untrained users would presumably delete their entire operating system accidently. If this was indeed a problem, I think they should have modified the program to make it more difficult to accidently trash your operating system by adding extra prompts and warnings for example, since it is a very useful command in some circumstances. Despite its notoriety, it was a fairly simple command as far as software goes, and the void was soon filled by programmers who released new versions on the Internet which did exactly the same thing only better; I wrote a utility to replace it as well but mine displayed a user interface if you specified the right command option.
