johnj@hijg.prl.philips.nl (John Janssen) (03/25/91)
I can not solve your FTP problem, but I have some 'news' about the floppy disk problem. It is known that HD (1.4MB) and DD (720kB) is not completely downwards compatible on PCs. And as the same DD disks are being used for the ST, the same problem goes for that as well. What are the problems: 1. HD drives use to make thinner tracks than the DD drives. 2. The material structure of the floppies is somewhat different. (Note: I'm not an expert in this latter area). Result: 1. A DD floppy, which is formatted on a DD drive will work perfectly. However, sometimes problems arises when the data written with a HD drive is being read with a DD drive. 2. A DD floppy, which is formatted on a HD drive may give problems when used with a DD drive. 3. A HD floppy, formatted on either HD or DD drive is a good reason for a lot of problems, when being used with a DD drive. What should you do, to be most-) lucky: 1. Always use a DD floppy disk. 2. Format it with a DD drive. (with other words: do not format it as DD with a HD drive) So format either on a ST (only when you have TOS 1.4 or a TT), or format it on a PC with DD drive. 3. Write the data on the floppy with a DD drive. This last step is not always necessary, as I found out that when you did at least step 1 and 2, you have a pretty good chance that the data written on the DD floppy with a HD drive, can be read in by means of a DD drive. However, it may be worthwhile copying the data to a DD floppy (or Hard disk of course), as you may get problems in the future. Hope this helps, John -- John Janssen Check the email address in the header, as this J.v.Deventerstr.1 may have been filled in wrong by the system. Venlo Holland +31 77 513177 Reply to: johnj@idms.prl.philips.nl
mc4c+@andrew.cmu.edu (Mark Choi) (03/27/91)
> Excerpts from netnews.comp.sys.atari.st.tech: 25-Mar-91 HD and DD > floppies (Was: FT.. John Janssen@hijg.prl.ph (1804) > 2. The material structure of the floppies is somewhat > different. (Note: I'm not an expert in this latter area). Nope, on both counts. You are not an expert :^), and there is absolutely no material difference between the two disks. This is a big lie from the disk makers to charge way too much for DS/HD disks. The only difference between the two, besides the extra hole, is that there are *sometimes* extra quality check on the DD and HD disks. Actually, even SS disks are the same. If they are given the hole, you can format SS disks to HD with no porblems. They (disk makers) just manufacture a batch of floppies, set aside a bunch to fill the SS order, and then test them for SS integrity. Then they fill their DD order, and test them, then they fill their HD order, and test them, all from the same batch. As the error rate in manufacture is fairly constant, the chances of a SS disk going bad are not that much more than off the shelf HD disks. This is why large fortune 500 corporations use devices like DiskDoubler to save money, and buy SS or DD disks. -geisha-
vsnyder@jato.jpl.nasa.gov (Van Snyder) (03/29/91)
In article <MbvwaYm00VIE08N4wf@andrew.cmu.edu> mc4c+@andrew.cmu.edu (Mark Choi) writes: >> Excerpts from netnews.comp.sys.atari.st.tech: 25-Mar-91 HD and DD >> floppies (Was: FT.. John Janssen@hijg.prl.ph (1804) > >> 2. The material structure of the floppies is somewhat >> different. (Note: I'm not an expert in this latter area). > >Nope, on both counts. You are not an expert :^), and there is absolutely >no material difference between the two disks. This is a big lie from the >disk makers to charge way too much for DS/HD disks.... [stuff deleted] On 5.25 inch disks, DS/DD (360K) and DS/HD (1.2M) use different coercivity media, 300 Oersted media for DS/DD and 600 Oersted for DS/HD. If you put a DS/HD disk in a DS/DD drive, you might fry the heads. -- vsnyder@jato.Jpl.Nasa.Gov ames!elroy!jato!vsnyder vsnyder@jato.uucp
mc4c+@andrew.cmu.edu (Mark Choi) (03/30/91)
> Excerpts from netnews.comp.sys.atari.st.tech: 29-Mar-91 Re: HD and DD > floppies (Was.. Van Snyder@jato.jpl.nasa (836) > On 5.25 inch disks, DS/DD (360K) and DS/HD (1.2M) use different > coercivity > media, 300 Oersted media for DS/DD and 600 Oersted for DS/HD. If you put > a DS/HD disk in a DS/DD drive, you might fry the heads. This is not the case with 3.5 inch disks, however. Several articles have been written about the subject in many magazines, and when asked, the disk manufacturers admit as much. They try to add stuff about non-tested reliability, but what it comes down to is that the disks are identical, and if it formats and works O.K., then it has just passed the test. You save by doing the test yourself.
Roger.Sheppard@bbs.actrix.gen.nz (03/30/91)
Distribution:world In article <8bx06Ry00WAw88BWUu@andrew.cmu.edu> mc4c+@andrew.cmu.edu (Mark Choi) writes: > > Excerpts from netnews.comp.sys.atari.st.tech: 29-Mar-91 Re: HD and DD > > floppies (Was.. Van Snyder@jato.jpl.nasa (836) > > > On 5.25 inch disks, DS/DD (360K) and DS/HD (1.2M) use different > > coercivity > > media, 300 Oersted media for DS/DD and 600 Oersted for DS/HD. If you put > > a DS/HD disk in a DS/DD drive, you might fry the heads. > > This is not the case with 3.5 inch disks, however. Several articles have > been written about the subject in many magazines, and when asked, the > disk manufacturers admit as much. They try to add stuff about non-tested > reliability, but what it comes down to is that the disks are identical, > and if it formats and works O.K., then it has just passed the test. You > save by doing the test yourself. Well here is my .02 cents worth, why is it that a lot of HD disks fail when Formating on DD drives ?? I am of the same opinion that HD disks do have a higher Oersteds than DD disks. Also if HD disks have been Formated on a HD drive to 1.4 megs, they can't be used on a DD drive, because of the lower Erase Flux of DD drives. They can't Erase the data, because of the higher Oersted of the disk media This has happened... -- Roger W. Sheppard 85 Donovan Rd, Kapiti New Zealand...
johnj@hijg.prl.philips.nl (John Janssen) (04/03/91)
In article <MbvwaYm00VIE08N4wf@andrew.cmu.edu> you write: >> Excerpts from netnews.comp.sys.atari.st.tech: 25-Mar-91 HD and DD >> floppies (Was: FT.. John Janssen@hijg.prl.ph (1804) > >> 2. The material structure of the floppies is somewhat >> different. (Note: I'm not an expert in this latter area). > >Nope, on both counts. You are not an expert :^), Yep you are right, I am not a material engineer, just an hardware and software engineer. and there is absolutely >no material difference between the two disks. This is a big lie from the >disk makers to charge way too much for DS/HD disks. The only difference >between the two, besides the extra hole, is that there are *sometimes* >extra quality check on the DD and HD disks. I think you are wrong here! There are differences, as I work a lot with both HD and DD floppies and floppy drives, and their differences drives me crazy-). It is almost impossible to use HD floppies with DD drives. You are really asking for troubles. Ok, I know there are exceptions, dependent on the brand. The only good results I had were with '3M' HD floppies, but then (see my original posting) format them with a DD drive, as this seems very important. I am talking about *REAL* experiences, and that learned me that most brands have different type of floppies for DD and HD. You do not need to take my advice, and learn it the hard way if that's what you want. My advice was only for all other souls around, who doesnot want to loose important files and waste their time by finding it out eventually. Actually, even SS disks are >the same. If they are given the hole, you can format SS disks to HD with >no porblems. They (disk makers) just manufacture a batch of floppies, >set aside a bunch to fill the SS order, and then test them for SS >integrity. Then they fill their DD order, and test them, Yep you are right here, but I was not talking about Single and Double Sided (SS and DS respectively), but about Double Density and High Density (DD and HD resp.). then they fill >their HD order, and test them, all from the same batch. As the error >rate in manufacture is fairly constant, the chances of a SS disk going >bad are not that much more than off the shelf HD disks. And here you go wrong again imo (see above). This is why >large fortune 500 corporations use devices like DiskDoubler to save >money, and buy SS or DD disks. > -geisha- Yep you are right again, as i think you are talking about one or two sides again. Note: a lot of different computers, a lot of different drives, a lot of different floppies, all from different brands were involved in our experience over a period from more than a year. So again, believe it or not. It's up to you! I only know the problems we had and the way we found (see original posting) to continue our actual work (which had nothing more to do with floppies than just being a storage medium). I just wanted to share our experience for those who wanted it. Success, John -- John Janssen Check the email address in the header, as this J.v.Deventerstr.1 may have been filled in wrong by the system. Venlo Holland +31 77 513177 Reply to: johnj@idms.prl.philips.nl