34 replies to this topic

[Marius1976]

I remember that the Atari ST had big trouble with handling HD discs (formatted at 720KB)

I was wondering: can a 1050/XF551 handle a 1.2MB 5.25" floppy disc like it is a 90K or 180K (or 360K) Atari formatted disc?

I know the drive will not see a difference, but is the data saved on these HD discs reliable?

Thanks
M.

[Bryan]

From what I've heard it's a bad idea. The flux transitions will be weak and the disk will be prone to failure.

[Stephen]

No - definitely not reliable. You won't damage the drive, but the data won't last either.

[Larry]

As the others have said, not a good idea. I never found any 5-1/4" HD media that was remotely reliable with our DD Atari's.

But... it really depends a lot on the specific media. There are some 3-1/2" disks that were rock-solid after several years. Others developed errors in a few weeks/months. And the same is true for 720K disks formatted in HD. Some terrible, and some just fine. I never even had real good luck with high-quality 1.44 disks with the Floppy Board in HD mode. Not many errors, but enough to be troubling.
-Larry

[Marius1976]

Hmm

How to determine what density a floppy is?

I have over 200 brand new 5.25" floppy discs without sleeve without lable.

I can use them; format writing reading but I need to be sure data is rather safe on it.

Are there any physical differences I can see with my eye, to see they are DD or HD.

[Larry]

There are a couple of indications, but nothing "concrete" unless stated on the jacket.

1. Most (but not all) HD 5.25 media did not use hub rings. Most DD (but not all) did use hub rings.
2. Most HD 5-1/4" is really "shiny" -- highly polished. This is not a great indicator, since some of the better brands of DD 5-1/4" media were well polished, also. But I have never seen any HD media that was "dull" like the majority of DD media.

-Larry

[31336haxx0r]

5.25" DD media appear to have a somewhat brownish appearance while the HD ones are black.

[Rybags]

HD ones contain Cobolt, so there's probably some way of distinguishing them.

Whether it can be done by non-destructo means is another thing though.

[31336haxx0r]

Wasn't it like it was with music cassettes back then? The ones with the brown tape were Iron (Fe2O3) based and the other (newer) blackish ones that needed higher field strengths were Chrome (CrO2) based?

[Marius1976]

I have opened a storage box, in where I found several boxes of -unlucky me- 5.25 HD disks.

I have looked carefully at them, and indeed the material of the magnetic foil is very dark and shiny.

But I also have a box with 3M floppy disks Double Density looking 100% the same (like Larry already wrote).
I also tried a HD floppy disk in my 1050 but everything worked fine.

Does this mean that the data on this HD floppy disk might not last (very) long?

Most of my disks (also the HD ones) do have the HUB ring.

I suppose that the disks I have here with no brand is Double Density. It is definitely lighter brown, and the material is not that shiny, but still not dull.

One more thing: I really have the idea that ABBUC is using HD floppy disks for their magazine. I got all my brand-new HD floppy discs from ABBUC when I purchased a few boxes two years ago. I ordered Double Density but I received these boxes. I never thought that it could be a problem, until I heard someone telling that it IS a problem on Atari ST. So that is where I start wondering...

[candle]

i never had any problems using hd disk in hd drive as dd disk on atari st
i don't have ajax chip, or hd modifications done inside, all i have is hd/dd switch permanently in dd position (hacked drive)
1.2mb disc are using a notch on top left corner to indentify in the drive that they are hd
drive will change current for write operations based on that notch

[Marius1976]

candle, on Sun Jan 22, 2012 12:24 PM, said:

i never had any problems using hd disk in hd drive as dd disk on atari st
i don't have ajax chip, or hd modifications done inside, all i have is hd/dd switch permanently in dd position (hacked drive)
1.2mb disc are using a notch on top left corner to indentify in the drive that they are hd
drive will change current for write operations based on that notch

Hi Candle! Thanks for your reply. I have investigated a few 5.25" HD floppy disks but I really do not see any physical differences (like notches). Could you verify that your information is concerning 5.25" disks?

The only reason I brought the "ST" up was because I heard from ST users that they had issues with HD disks in their default DD drives.

I thought: hmm if THEY have issues... perhaps using HD disks in 1050/XF551 would cause issues too.

I hope you can confirm that 5.25" HD disks have that notch or not. I could not find it.
Thanks
Marius

[31336haxx0r]

I can't remember seeing ANY notches on those disks except write protect and index hole..

[candle]

hm, thats wondering
i don't have any HD 5.25" disks right now, so i've based my assumption on presence of additional sensor in HD drives versus lack of it in DD drives (got bunch of 1.2mb drives with these sensors, and just a single 360k drive that doesn't have one - maybe its for something else then)

[Marius1976]

Yesterday I found an interesting document about Disk formats (history and technical information).

http://www.retrotech...tuff/drive.html

Today I format a 5.25" HD floppy disk with my Happy 1050. No problems so far. I filled the floppy with SpartaDos 3.3a and Bobterm. The disk booted fine... but after I removed the disk and reinstalled it in my 1050 it refused to boot. After a new try it booted again.

I'll try this disk tonight again, and tomorrow, and in a month. I'm just curious how reliable this is going to be.

I understand that there is a difference in magnetic strength needed for HD disk coating, and that is the (only?) reason that it does not work.
A lot of HD 5.25" might not have HUB rings, after investigating my stock, most of my HD floppy disks do have the hub ring, so that would not be a problem for my drives.

One lost very interesting thing:

I also have a bunch so called SINGLE SIDED disks. This is very odd... (really!) ... since there do exist single sided diskdrives with the read/write head on the top, and there do exist single sided diskdrive with the read/write head on the bottom side of the floppy disk. So how can a manufacter of Floppy disks know what drive I have?

Somewhere I read that Single Sided disks only have ONE verified side and that the other side might work, but not guaranteed or something.

Interesting all this.

[Larry]

Upgrading and Repairing PC's has a wealth of information on this subject that you might find useful. If you don't have a copy, your local library might.

-Larry

[bbking67]

I remember the single sided discs... the ones i had were BASF and I believe that I was able to use the other side on an Atari with no issues. These were the earliest discs I had and I probably don't have them anymore. BASF with a brown label and sleeve.

...and thanks to google images i found a picture of the exact one i remembered!

I worked at a store called Consumers Distributing and I only bought them because they were very cheap on clearance (discontinued). That would have been 83 or 84.

http://dcsutherland....513_wKrdx-L.jpg

Edited by bbking67, Mon Jan 23, 2012 8:11 PM.

[Marius1976]

Is there already a tool available that fills a disc with a certain usefull patern and give the possibility to verify the disk later.

I know I can do a verify on write in Dos, but I mean something different.

I want to fill a disk with a pattern.
Store the disk for days, weeks, months, even years.
and THEN verify the disk.

If this does not exist, I'll write it myself.

I wrote something similar years ago to test my ramdisk. that tool filled my extended ram with a certain pattern and left to dos. the other tool (the verifier) checkt the extended ram for the same pattern, if an error occured it wrote an asterisk (*) on the screen, if no errors where found it printed the line "no errors" on the screen (how appropriate). The coolness of this tool was that it gave me the option to run 'heavy' software (64k max ofcourse) for days and then to check the extended ram again.

When the ramdisk was still fine after a few weeks I was pretty sure that the ramdisk was fine indeed.

I guess this would also be a very fine solution for real disks. So that's the question:

Does such a tool aready exist?

Greetz
M.

[Fox-1 / mnx]

Just get a DD disk and fill it with files up to the end. Preferably files which don't have big block of zero's. Binary files will usually do.

Write a small tool to read the disk, sector by sector, starting at sector 4, and calculate a checksum. Write down the checksum or even post it here so it can be found again in some time. Repeat this a few times to be sure you always get the same checksum.

Copy the DD disk to an HD disk (or multiple disks) with a sector copier which doesn't skip empty sectors. Write-protect the disk(s). Read the disk(s) again with the tool to get the checksum.

[Marius1976]

Yesterday I wrote the little tool. It's a really stupid and simple tool, and it just formats a disk on single density (why, I explain this later). And fills al 720 sectors with the same pattern: $00, $AA, $FF, $55 (repeated 32 times on each sector).

The other tool reads all 720 sectors and after each sector it verifies whether the pattern is (still) there. If not the screen turns black.

That's all what the tools do. But it was rather interesting.

I have several types of HD floppy disks and I found out that I have one batch of one brand that does actually work good.
The others fail.

I have an older batch of MEMOREX HD floppy disks. The label (with a RED memorex LOGO) sais: MEMOREX 5420 5.25" 2 S/ 4 D and there is also a "10" on the label. These disks work perfect in my 1050. (And yes... I have other prove of that, read on!) The magnetic foil is not as dark as other brand HD floppy disks I have. These disks also have a HUB ring. I also have a very special batch of the same memorex disks. These have darkgrey label. Also with the RED logo. Also 2s/4D printed on the label. These disks work fine too.

I also have a newer batch of MEMOREX HD floppy disks. These have a blue logo printed. The magnetic thing inside the floppy is more black. These disks don't have the HUB ring, and the label also reads 1.6mb. These disks refuse to work. So do also my BAS-F HD floppy disks and my 3M HD floppy disks.

Why am I rather sure the old batch memorex HD disks are good to use.

Well... the non-working batch of HD disks resulted in problems after only a few minutes (!). When I verified the disks just after writing the pattern, they gave no problem. But on the next verify I also heard the drive head having issues. And after another time, there showed up the problems.

The older Memorex disks kept giving good results.

Ok you would say now: but you wrote the test-tool YESTERDAY. How can you be so sure, the data on these disk will last longer.

RIGHT! That was the same thing I thought and said to myself. So I went searching in my floppy disk collection.

And what did I found! YES! I found 6 floppy disks of these OLD Memorex Batch which I used 3 years ago when I was creating a nice floppy box (that was a time I really want to go retro, and only use floppy and tape, in stead of blackbox, myide, sio2ide etc).
I found several games, and... (VERY interesting) a dual sided MEMOREX HD Floppy disk with NUMEN on it.

I booted the disks... and I watched numen. NO problems.
I played the games on the memorex HD disks. NO problems.

Today I rechecked my test disks (with the pattern). They still verify VERY stable. From the first to the last track. No trouble.
Tried other 1050's no problem.

Ofcourse you'll never know. But that the disks DO work after 3 years, and that with my test results described above (and especially when you also look at the test results of the non-working HD disks) I'm pretty sure these disks are safe to use.

One more thing:
First I thought it is the WRITING that is the problem. But I believe now that is not really the problem. All the disks that failed, do still carry the right pattern. After re-reading failing sectors several times, I get the RIGHT pattern on the screen. The recording of the data is probably too weak to read right.

I found out that my happy drives do have less problems. Perhaps because they read tracks in stead of sectors? I have no idea.

I will take a picture of the WORKING disks. Might be interesting when you need to buy floppy disks.

[Marius1976]

Why Single density.

It's simple. This tool is not meant to check for bad sectors. It is just made to test whether a type of floppy disk can be used or not.

If this works on single density it will work on double too.

I wanted to test this on my stock 1050. Especially when I found out that my happy 1050 drives (I have 4 happy drives) had no problems. I thought: hmmm let's test this on stock 1050, and then I realised: oh ... but they don't read double density. So I changed the tool to single density.

And yes: after that I checked AGAIN on my happy drives, which still have no problems with HD floppy disks (even in this single density)

Strange, since the head in happy drive is still the same as in stock 1050. But ok.

[Ransom]

I'd have to check the exact product number, but the Memorex HD floppies I bought back in the mid-90s to use with my XF551 in DSDD mode (with SpartaDOSX) continue to work fine. I've never used one in dual density mode or with a 1050, though. I tended to use the generic DSDD floppies for that, back then.

[Marius1976]

Yeah. These Memorex (older) High Density disks appear to be an exception. Perhaps these are not 'real' HD disks, but only sold as HD. I won't be surprised when these Memorex HD disks are not so reliable in real HD mode. But that is not my point of interest. They work fine. Nice to know.

[bf2k+]

Marius1976, on Wed Jan 25, 2012 3:49 AM, said:

I have an older batch of MEMOREX HD floppy disks. The label (with a RED memorex LOGO) sais: MEMOREX 5420 5.25" 2 S/ 4 D and there is also a "10" on the label. These disks work perfect in my 1050. (And yes... I have other prove of that, read on!) The magnetic foil is not as dark as other brand HD floppy disks I have. These disks also have a HUB ring. I also have a very special batch of the same memorex disks. These have darkgrey label. Also with the RED logo. Also 2s/4D printed on the label. These disks work fine too.

These sound ike the old Quad density disks I had back in the 80s for use with the quad density drives I had on my BBS. I had a box of Memorex and 1 of Maxells. The Quad density drives were plugged into an Amdek 3" dual disk drive that had a controller for external drives bult into it.

[bob1200xl]

HD disks refer to the r/w frequency that is used on the track, something like 4mhz or 8mhz. Old disks that are marked QuadDensity or HD were referring to the TPI (tracks per inch) and lower frequency encoding, like 1 or 2 mhz. An 80 track drive will still write the data at the same frequency as a 40 track drive. A real HD drive writes data at the higher rates.

Don't get mixed up by old references. Any diskette with hub rings and tan oxide is a Low Frequency disk. No hub ring AND black 'oxide' is a High Frequency disk.

You cannot use a HF diskette on an Atari - period. If you have HD diskettes that work on a 1050 (any 1050), they aren't...

Trying to verify a diskette is not viable since some diskettes fail over time, no matter what they are. The binder goes bad and the coating scrapes off and you lose your data. Not often, but sometimes.

Clean the head with with a good head cleaner or you will spread the joy to other disks...

Bob