I really liked the Atari 400, but it did have some problems. The obvious first problem was the terrible keyboard. Sure, it was better than some of the awful membrane keyboards of the time, but it still was not good.

Also, it only had 16K of RAM. This meant there was a lot of software that wouldn’t work with it and it also meant that you really couldn’t use a disk drive with it since loading DOS used of a noticeable amount of the precious RAM.

So at some point in 1984 we upgraded to an Atari 800XL. I suspect this would have been later in 1984 after Atari was sold (a crazy story in its own right) and started drastically dropping the price of the 800XL, which was a revelation compared to the 400.

The 800XL had a (mostly) standard typewriter keyboard. It had 64K of RAM. It had a built-in BASIC (even if it had an annoying bug) and the cartridge port on the top was much easier to use. Plus, it was much more stylish and modern-looking with its white and charcoal color scheme. It still looks great today, in my opinion.

I much preferred typing on this, as you can imagine, even if it had odd placement for some keys. For example, the double-quote is on shift-2, which is weird. That really messed me up when I was learning to type on IBM Selectric typewriters.

Although we first used this with the cassette recorder we had with the 400, we quickly added a 1050 floppy disk drive. Then a Star SG-10 printer, which was the printer to have back in the day — better and cheaper than an Epson, but compatible. We even got a 2nd 1050 disk drive at some point, which made it much easier to copy files and disks.

I used the 800XL right through high school, where I learned more BASIC and Pascal programming (Kyan Pascal — I’ll have more to say about that in a later article). I used it to write many papers using the amazing Paperclip word processor and printed them in Near Letter Quality (NLQ) on the Star SG-10 printer. If you’ve ever used NLQ, you are now hearing those noises in your head (screeeeeech, screeeech). It was so loud. And so slow. But it looked good enough that teachers would accept a paper with it so that you didn’t have to type it on a typewriter.

Back to the disk drives.

By default the Atari 1050 disk drive supported something called “dual density”. To back up a bit, the first Atari 810 disk drive was single density so it stored about 90K on a 5 1/4” floppy disk. A double-density disk would store 180K on a disk.

A disk was divided into sectors. The Atari disks had 720 sectors on a disk. The density referred to the number of bytes in each sector. A single-density disk had 128 bytes per sector. So 720 sectors x 128 bytes per sector = 92,160 bytes per disk. Divide that by 1024 and you get 90K.

A double-density disk had, you guessed it, 256 bytes per sector. So it had exactly double the capacity per disk, or 180K.

Back to the 1050, it had something called “dual density”, which used single-density sectors, but had more of them (about 1000 if memory serves). So it could fit about 120K on a disk.

Why Atari chose to use this odd format remains a mystery to this day, but it probably just comes down to money: single-density drives were cheaper.

But worse, the Atari 1050 came with the terrible DOS 3. With DOS 3, instead of getting the smaller sector sizes, it grouped things into blocks of 120 blocks of 1K. Back then, files could be small, so this wasted a lot of space. DOS 3 was also incompatible with the much more widely used DOS 2 that had been around for years at that point.

Eventually Atari remedied this with DOS 2.5, which added dual-density support and backwards compatibility. I remember spending a lot of time using a utility from Antic magazine (Escape from DOS 3) to get files off our DOS 3 disks on onto DOS 2.5 disks. I think a cassette was involved somehow.

Anyway, this is getting a bit long and I have more to say about how we upgraded the 1050 drives to true double-density with the US Double chip. And I definitely have to talk about the amazing SpartaDOS. And Atari BASIC, BASIC XE, Turbo-BASIC XL and so much more.

If you liked this post, you might like this one as well:

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Inside the Atari 800XL

Although I now have an Atari 800XL, it is not the one I had as a kid. This one is a later model because it has the Rev. C BASIC built-in. It is not modified in any way. If you zoom in on the picture below a bit, you’ll notice the Option key is somewhat worn out. This is pretty common because you have to hold down Option to disable the built-in BASIC, wh…

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10 months ago · 15 likes · 8 comments · Paul Lefebvre