34
votes
Accepted
Why are the magnetic floppy disk drives (FDD) heads not frictionless?
TL;DR:
"Frictionless" Floppies are called Hard Disks (*1), consisting of a hard media platter and a head in distance of the media (flying or otherwise)
Floppies are 2D tapes. While slower ...
- 223k
32
votes
What "spectacular to watch" algorithms were used for sorting tapes?
Sorting on tape is actually mostly merging. And the canonical never-to-be-surpassed source of information on that is Knuth's masterwork The Art Of Computer Programming1 (aka TAOCP). Specifically ...
- 6,269
28
votes
Accepted
Why were closed tape loops never a popular storage medium (or were they)?
Because a closed tape loop doesn't buy you anything in random access latency, which is presumably the problem you're trying to solve.
The problem is that large tape loops, like 8-track, only can ...
- 649
24
votes
Accepted
How does a floppy drive identify the first and last sectors and tracks?
The track identification part is quite simple. Floppy formats are standardized so that there are specifications what is the distance between tracks (e.g. 96 tracks per inch) and what is the position ...
- 32k
23
votes
Why were closed tape loops never a popular storage medium (or were they)?
They were used, but suffered from latency issues and complex electro-mechanical design challenges. Their brief day in the sun was around the mid-1950s: after that, it was likely cheaper to add another ...
- 21.6k
23
votes
Accepted
What was this mini-computer tape troubleshooting process
While I can't be certain, what you describe sounds like some variation on what's mentioned in the description of Techmoan's The Magnetic Tape Viewer - see the sound on a tape:
Q) You can buy these ...
- 6,765
17
votes
Accepted
Help identifying format of old tape backup
I ended up figuring out that this backup was made using an extremely obscure tool called TXPLUS, which was a proprietary backup utility shipped with TapeXchange tape drives, which were tape drives in ...
- 755
15
votes
What "spectacular to watch" algorithms were used for sorting tapes?
The fastest tape sorts were proprietary variations of polyphase merge sort that could take advantage of tape drives that could read backwards for 3 to 7 tape drives (for 8 or more tape drives, ...
- 631
13
votes
Accepted
Was sneakernet a job description?
That quote sounds quite chaotic. My experience about tapes (and disks) moved to/from storage in /370 installations is of orderly carts made to hold up to 50 tapes or 6-8 disk stacks, fine labelled and ...
- 223k
13
votes
Accepted
What is the best way to connect an old Tandberg QIC tape drive using today's computers?
The back looks like a 50 Pin Centronics. I am just not sure how I can connect such a device using modern computers, if at all. Any suggestions or guidances would be much appreciated!
Well, it seems ...
- 223k
13
votes
Accepted
Magnetic tapes as a random access medium?
DECtape was used that way; it was wide (0.750 inch?) magnetic tape, on very small reels, so it
didn't take forever to find a sector. PDP-8 and PDP-11 systems from Digital Equipment were the likely ...
- 2,170
12
votes
Why are the magnetic floppy disk drives (FDD) heads not frictionless?
The head gap must be very narrow to be able to make sharp magnetic transitions on the moving magnetic media. It also means the magnetic field does not bulge out too much out from the head so the ...
- 32k
11
votes
Why were closed tape loops never a popular storage medium (or were they)?
unlike with big drums or disks, you don't need to carefully align the heads on a huge surface but can just let a small part of the tape come to the fixed head.
Sounds a bit like you never had to do ...
- 223k
11
votes
Developing an application in the era of cassette tapes (audio-tapes)
Obviously, you can just switch tapes as you go, but systems that used cassette tapes for storage weren't really viable for collaborative development.
Simply because with a cassette tape, you had "...
- 12.3k
10
votes
Developing an application in the era of cassette tapes (audio-tapes)
Probably, no serious software development was done purely on tapes.
Floppies were used extensively, as well as cross-tools, ROM emulators etc.
This nice and free book, telling about the creation of ...
- 10.4k
10
votes
Accepted
Why does a DECtape have 576 blocks?
The standard tape reels had a capacity of 260 feet of tape. Standard tape thickness was 1.25 mil, so it would have theoretically been possible to put more tape on a reel if you made it thinner (which ...
- 11.4k
9
votes
How does a floppy drive identify the first and last sectors and tracks?
Where there are various formatting schemes for floppy disks, the usual is to break down a track into sectors. This is done during formatting and the individual sectors are written with empty data in ...
- 3,049
9
votes
Accepted
What information could be recovered from visualized magnetic information?
What information could be extracted from visualized magnetic information?
The very same as with a magnetic head: flux changes - and from there everything else, like headers, sectors and the data ...
- 223k
9
votes
Could visual inspection of the magnetic disk be used to detect the quality (or damages) of a floppy disk?
Visual inspection, without special lighting, can reveal the most common types of damage to floppy disks: mold, and damage to the medium (up to delamination). You can see examples on this page on disk ...
- 122k
8
votes
Why were closed tape loops never a popular storage medium (or were they)?
Closed tape loops may not have been popular, but they were used occasionally.
One of the first computers, Colossus, used a paper tape loop for read-only data storage (the ciphertext to be decoded ...
- 481
8
votes
Accepted
Using audio tape recorders on non-personal computers?
TL;DR
Yes, there where several professional mainframe (related/connected) devices that did use analogue recording. Most of them developed arround 1970 and used until the early 80s.
The key reason to ...
- 223k
8
votes
Magnetic tapes as a random access medium?
There's another use of tape drives that is "sort-of" random access and floppy-like, besides DECtapes: The Exatron Stringy Floppy and the ZX Microdrive used tapes that consisted of a closed loop in a ...
- 27.3k
8
votes
Was sneakernet a job description?
In the company I worked for, there certainly weren't people "running around" with tapes etc. The "tape library" was a whole department, and the physical storage occupied almost a complete floor of the ...
- 6,656
7
votes
Why were closed tape loops never a popular storage medium (or were they)?
There are two ways to achieve a tape loop:
Keep all of the tape perpendicular to the same plane, and add enough rollers that the tape never has to wrap against itself. This approach works well for ...
- 36.2k
7
votes
Developing an application in the era of cassette tapes (audio-tapes)
What about complex applications?
You bought a floppy drive, or before that, used punch tape. The period where cassettes were the only form of storage on micros was basically zero.
Up to about 1976 ...
- 20k
7
votes
Accepted
How did IBM's "Mag Card" drive and magnetic media work?
The fascinating thing to me is the way in which the media is a hybrid of a punched card and a floppy.
It's more like a floppy - especially in its original version, the IBM 2321 Data Cell Drive of ...
- 223k
7
votes
Accepted
What is the effect of direct exposure of the magnetic disk of a floppy to ultraviolet (UV) light?
UV light won't affect the magnetic signal.
It will however degrade most plastics. UV has energetic photons, that can break apart the molecules in the plastic, thereby degrading it. This has nothing to ...
- 298
6
votes
What is the best way to connect an old Tandberg QIC tape drive using today's computers?
The first thing you need to do is to open the front door of the drive and inspect the rubber roller that drives the tape. It is not uncommon for the roller on old drives to have deteriorated into a ...
- 11.4k
6
votes
Developing an application in the era of cassette tapes (audio-tapes)
It depends a lot on the machine, the job and your team size and what time we're talking.
Professional developers usually didn't work on the same minimal setup as their target user. Especially in the ...
- 223k
6
votes
Cheapest way to store and load small dataset in the 80s?
Punch cards were the cheapest storage medium for small data sets. Remote Job Entry terminals such as used by Control Data Corporation included a card reader and line printer. The initial member list ...
- 710
Only top scored, non community-wiki answers of a minimum length are eligible