Showing posts with label floppy disk. Show all posts
Showing posts with label floppy disk. Show all posts

Tuesday, March 2, 2010

Trouble with the Floppies

In my first years of computing my experience with floppy drives was pretty good. I had used several computers for thousands of hours total, and had seen hardly a hiccup reading and writing floppy disks.

The computers I had experience with floppies included:

Apple II+
IBM PC
Heathkit H-89

These used brands like Shugart and Tandem for their floppy drives.

Working with Patrick Alessi there was little trouble. He did smoke a pipe constantly around the equipment but this didn't seem to cause any problems.

At C.F.C. it seemed like floppy disks were more temperamental. Not that they weren't reliable enough for day to day use but they would cause problems just enough to be annoying. Maybe it was the industrial environment, or maybe the quality level for drives and floppy disks was falling. I dunno. Some of our disks came from customers and were formatted by their computers, so maybe that also had something to do with it. Floppy disks had become cheap and didn't have the same quality they did a couple of years earlier.

Some floppy drives could be calibrated using software and a screwdriver. I did try some of that, but I can't say I remember it being very successful.

Monday, February 22, 2010

101 Things You Can Do With a Floppy Disk

C.F.C. hired a college student for the summer of 1987 to operate their TRS-80 system which had three 5.25 inch floppy drives. The young student (he might have been older than me) would sometimes come to me when he had computer questions or if the machine wasn't working perfectly.

So, one day he comes to me and says that he's getting errors from the floppy drive. Okay, I followed him over to the computer. He reaches over and perfectly naturally reaches down, opens the drive and pulls out the disk... backwards! The disk was in the drive backwards, and his fingers were touching the magnetic disk through the access hole. I wasn't ready for that, and I don't think he was ready for my surprised outcry!

The good news? Even with fingerprints on the disk surface the data was still intact. The disk read fine when it was reinserted correctly.

Monday, June 11, 2007

Floppy disks

In the early micro days we used cassette tapes and floppy disks. Floppies were better for many reasons but they were expensive. The Apple Disk II drives were $495 including the controller. Once you had one of these babies you still needed floppy disks. I remember pretty clearly in the early 80's spending $80 for a box of 10 floppy disks. These were Dysan disks, and were of very good quality.

However these disks probably exceeded the quality required. Later on some less expensive floppy disks became available from the likes of Maxell and memorably named Elephant Memory Systems. These were $2.50 or so per disk. The disk surfaces weren't as polished, and some cheap brands didn't have a reinforced mount but no matter really. The cheap disks were pretty much as reliable as far as anybody could tell.

Disk drive systems themselves were all quite different from each other. Apple's legendary Steve Wozniak had managed to create the ultimate in economy of design for a disk controller with a small card having only 5 ICs. Most other disk controllers were long circuitboards with 2 to 3 dozen chips. Monsters. ;-)

Some of these floppy drives used hard sector disks, meaning that there was an index hole in the media for each sector on the disk. So, if the disk was meant for a 16 sector drive, the disk would have 16 timing holes cut out of it evenly around the inner part of the disk. This would be read by an LED and a sensor. The Apple II used soft sector disks where there was only one hole cut in the disk, and the drive controller itself decided how many sectors to put on the disk by doing careful timing.

I remember that my father's H-89 had hard sector disks. The drives also made a strange clunking noise as they operated. The Apple II's drives made the much more familiar brrrr, brrr, mmm, mmm sound of most floppy drives and they were faster than the H-89 drives.