Why tapes are better than discs

[PaulQ]

I always thought that computer cassette tapes had certain advantages over discs that went largely unrecognized. Number one is the fact that they're great for a spy and anyone wishing to conceal illegal bits of code; the computer data or program can be easily hidden on a music cassette. I was always surprised that movies didn't exploit this in their plots. I also thought that tapes were never exploited to their fullest potential; they could've been made to operate a lot faster as they did in the ADAM. So, here's another list; this one dedicated to Why Tapes are better than Disks:

1. Perfect way to hide code for spies and hackers.

2. Virtually indestructable, compared to fragile disks.

3. Very reliable.

4. No formatting required.

5. Cheap and readily available.

6. Very long shelf life.

Time for the members of Denial to complete this list...

[eslapion]

One of the reason floppy disks are less reliable is because the amount of data stored on outer tracks (cylinders) is just about the same as that stored on inner cylinders which are much smaller.

Altough this is less obvious on a 1541, for example, which does have fewer sectors on inner tracks than on outer tracks, the compensation is not enough to be able to say the data density is the same on all tracks.

CDs, with a constant linear velocity, however, do offer a data density which is the same on all cylinders. And therefore, each tracks has a slightly different amount of data stored on it.

With a tape, however, with a perfectly regular magnetic material flow, the data density on the magnetic surface is always perfectly even. While a 1541 disk can carry up to 320k if used on both sides, an ordinary 90 minutes cassette tape can carry more than 1Mbyte of data when saved at a speed similar to that of the rabbit tape accelerator.

Normal audio tapes are too slow for modern computer applications. However, DATs and DLTs are very popular in the industry. Modern Digital Linear Tape systems can store up to 1.6 TeraBytes on a single tape cartridge.

They use tape with a helical scanning system not too unlike what is found inside a good old VHS VCR.

[Jeff-20]

For VIC programs, there are more variations among tape decks than disk drives. I've recorded programs on tape that could not be read on another drive because they were slightly out of sync/alignment. I've never had this problem with disks.

I also have tapes I have received from other programers years ago that cannot be read today. I have no idea why, but disks from the same time or earlier are fine. Tapes seem to degrade quickly.

Commercial tapes are much better but I am uncertain why this is the case. Car Chase loads perfectly, but something I put on tape is dead within a year. Obviously quality is key. But how can one predict the quality of unmarked tapes such as the box of brandless tapes I have here.

My VHS tapes were also clearly aging before I transferred what I wanted to DVD.

[Boray]

The diskdrives has some kind of auto alignment when it's starting to load. It probably moves the head around until it finds something to read. So I guess this is why it works better between different disk drives than with tapes...

[PaulQ]

But how can one predict the quality of unmarked tapes such as the box of brandless tapes I have here.

One can determine the quality of a cassette tape by examining the colour of the tape itself. Poor quality tapes are typically light in shade and brown in colour, while higher quality tapes (both pre-recorded and blank) will be very dark; the closer to black, the higher the quality. I have some black Maxell tapes from the 80's that play perfectly today, while the cheap ones with a much lighter and brown coloured tape are so faint, they're barely audible.

[ral-clan]

I agree that cheaper tapes are generally lighter in colour (some being almost orange) while better quality tapes don't use iron oxide, but some other formulation that is almost black. There are some Type I cassettes that you can buy which are very dark. Type II cassettes (i.e. Maxell High Bias) are almost always jet-black.

However, I would caution against using Chromium Oxide (High Bias Type II CrO2) cassettes in a datasette. When a datasette records a signal onto a cassette, it is (I assume) optimized to record to a Ferric Oxide (Type I) tape. While the physical quality of Type II tape is better, because the datasette is not outputting a signal at the correct bias for this type of tape, the recorded signal will be less reliable (fainter & more noise). That's why good quality tape decks have switches to set them to record on each type of tape (Type I, Type II, and Type III - or METAL).

One disadvantage of cassettes is the fact that they can stretch over time. This can cause big problems for the datasette - especially if some area of the tape is stretched more than others. This is why it's important to use the shortest length cassette you can get. A 90 minute or 120 minute cassette has a thinner plastic substrate which can stretch more easily. Back in the 1980s you could buy 10 minute cassettes just for computer use. Today I think the best you will be able to find is a 60 minute cassette. Also, this is another reason to buy a brand name cassette rather than a cheap no-name brand.

But overall, I love using cassettes. I find them very reliable. I always back up my programming to cassette and this has saved me a few times when my diskettes proved unreliable (due to alignment problems).

I also enjoy loading a game from tape now and then for the nostalgic, authentic experience.

The other great thing about cassettes is something we mentioned on another thread: you can still buy brand new, recently made, fresh cassettes at your local store. Buying brand new 5.25" disks is going to be a little harder.

[carlsson]

I don't agree on "virtually indestructable". Have you ever had a tape that breaks in the middle of a program being loaded? Perhaps a tape which winded itself around the mechanism, resulting in a "fur ball" of tape? In that respect, I think 5.25" floppies are just as durable as long as you store and use them with care.

[PaulQ]

I've had tapes that were fully submerged in water work fine after being dried out. Aside from that, yes, I have had "Cheap" tapes break and get chewed up. By "Virtually indestructable," I'm talking about the physical characteristics of a good quality tape; pretty much immune from dust, dirt, and even water.

[MacbthPSW]

I also thought that tapes were never exploited to their fullest potential; they could've been made to operate a lot faster as they did in the ADAM.

Yes, though it seems the ADAM's tape drive is notoriously unreliable. Whether this is a result of the drive being "too fast" or another design flaw, I don't know.

[PaulQ]

I also thought that tapes were never exploited to their fullest potential; they could've been made to operate a lot faster as they did in the ADAM.

Yes, though it seems the ADAM's tape drive is notoriously unreliable. Whether this is a result of the drive being "too fast" or another design flaw, I don't know.

The only problem I'm aware of is that the tapes would erase if you left them in the tape drive while powering up the ADAM. Other than that, they worked fine. While I agree it is a significant design flaw, I don't think it has to do with the high speed the tapes operate at.

[eslapion]

For VIC programs, there are more variations among tape decks than disk drives. I've recorded programs on tape that could not be read on another drive because they were slightly out of sync/alignment. I've never had this problem with disks.

I also have tapes I have received from other programers years ago that cannot be read today. I have no idea why, but disks from the same time or earlier are fine. Tapes seem to degrade quickly.

Commercial tapes are much better but I am uncertain why this is the case. Car Chase loads perfectly, but something I put on tape is dead within a year. Obviously quality is key. But how can one predict the quality of unmarked tapes such as the box of brandless tapes I have here.

My VHS tapes were also clearly aging before I transferred what I wanted to DVD.

Altough it is perfectly true that head alignment is a far more complex business with compact cassettes than with floppy disk drives, tape drives, audio decks or datassettes have much less tendency to fall out of alignement.

Also, assuming the cassette deck writing and reading the cassette are running the tape at the proper speed of 47.6mm/s or 1 7/8 inch/s and have good head alignment, the truth is data or audio recorded on cassette lasts longer than on floppies and is more resilient when exposed to magnetic signals capable of causing erasure.

The reason why what you put on tape might be dead within a year is probably because the RW head of your datasette has become magnetized and erases tapes. A good demagnetizing treatment is in order.

Since I have used the same datasette since 1983, I stumbled upon problems similar to what you mentioned. I had a nice collection of commercial tapes I couldn't read anymore. I suspected the problem wasn't with the tapes when I put the tapes in my good old Technics RS-B14 audio tape deck and looked at the signal with my oscilloscope. They looked perfect.

Since the audio experts could not realign or adjust the datasette for lack of output type they were familiar with, I decided to get my audio deck realigned. Then I used wav2prg to convert the audio captures to prg files and... voilà... my old programs worked again!

See: http://en.wikipedia.org/wiki/Compact_cassette

[eslapion]

I don't agree on "virtually indestructable". Have you ever had a tape that breaks in the middle of a program being loaded? Perhaps a tape which winded itself around the mechanism, resulting in a "fur ball" of tape? In that respect, I think 5.25" floppies are just as durable as long as you store and use them with care.

This sort of mishaps is ALWAYS caused by a dirty rubber roller. Always remove the oxide that accumulates on the rubber roller with near 100% pure alcohol.

If the rubber becomes dry after a few years, then use rubber renew to give it back its original flexibility.

The tape themselves, when compared to floppies, are relatively indestructible. Of course using 25 cents 120 minutes tapes is not a good idea.

The link I gave in my previous post lists the difference in thickness between different cassette rated durations.

[carlsson]

For that matter, I doubt any manufacturer of computer tape recorders ever recommended longer tapes than C-30, perhaps even C-20 or C-15 for recording data, and only on one side. Those of us who with relative success used loads of C-60 and C-90 and recorded both sides with Turbo Tape 64 probably are an anomaly that it worked as well as it really did.

[ral-clan]

One of the problem with the ADAM tape drives was that there was something in the computer directly behind the drive bays that emitted a strong electromagnetic field. This would actually erase the ADAM cassettes after a time.

The idea wasn't a bad one though. Other companies offered their versions of a "stringy-floppy" accelerated tape drive. For a time in the early 80s it looked like they actually might catch on, but for some reason they didn't (maybe the price of drives came down)?

What about CD-ROM as a storage medium for reliability (obviously not for the VIC)? When they first came out manufacturers were claiming 100+ years of reliable data storage. After being in real use, people are finding their data is fading after only a few years! This is a big worry for people with large libraries of irreplacable photos, etc. Meaning they have to back up their back ups all the time.

[PaulQ]

What about CD-ROM as a storage medium for reliability (obviously not for the VIC)? When they first came out manufacturers were claiming 100+ years of reliable data storage. After being in real use, people are finding their data is fading after only a few years! This is a big worry for people with large libraries of irreplacable photos, etc. Meaning they have to back up their back ups all the time.

Again, there is still always tape backup. I shoot all of my family video on mini DV tape for that reason. Hard drives eventually fail, recordable DVD media fades, but good quality tape is the only proven method of long-term data storage. Now, if only I could figure out how to back up my pictures to a MiniDV tape...this might work:

http://www.jakeludington.com/project_st ... amera.html