petcher@wuphys.wustl.edu (Donald N. Petcher) (03/23/91)
This is for people who use a NeXT and also an Atari ST or alternatively an MS-DOS machine, and interchange disks between them. I don't know if my problem is related to the Atari side or if my NeXT is just not behaving properly. I myself have a NeXTstation, and an Atari ST, and when I format an IBM compatible 720K MS-DOS disk on the Atari, the NeXT seems to have no problem reading it. However, if I write anything on the disk with the NeXT, and then try to get the Atari to read it, it always acts as if the disk is damaged and the files are unreadable. I have been able to get the Atari to read a couple of small files but that is all. For those who know the Atari, I format the disk always 80 tracks, 9 sectors per track, and sometimes twisted (desktop, TOS 1.4), or untwisted (GPshell or DC Formatter) and then add an IBM boot sector with DC Formatter. That works fine when swapping disks with a PC. I would like to know if this is similar to others' experiences or if it is peculiar to my system. Also is there a way to format an IBM compatible disk using the NeXT? Any help or testimonies of experience (including from NeXT/IBM clone users) would be appreciated. Don Petcher petcher@wuphys.wustl.edu petcher@wuphys.uucp
sstreep@next.com (Sam Streeper) (03/24/91)
In article <1991Mar22.211223.15978@wuphys.wustl.edu> petcher@wuphys.UUCP (Donald N. Petcher) writes: >I myself have a NeXTstation, and an Atari ST, and when I format an IBM >compatible 720K MS-DOS disk on the Atari, the NeXT seems to have no >problem reading it. However, if I write anything on the disk with the >NeXT, and then try to get the Atari to read it, it always acts as if the >disk is damaged and the files are unreadable. I have been able to get >the Atari to read a couple of small files but that is all. This is my experience too. IBM compatible formatted disks from the Atari read fine on the nextstation, but going the other way is problematic, and reads fail if the file spans more than about 3 sectors. Here is my guess as to the problem: When you write 720K disks on the atari, you write the sectors as comparatively strong, fat tracks. A single data track is fairly wide, so a single track looks something like this after formatting with 0xE5 as a formatting value: E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 The NeXT drive by default writes tracks twice as dense and half as narrow, which is how it offers 4x the data capacity. When it senses that it is writing a 720K dos disk, it writes the data at the same data density and track spacing of a DOS disk, but the tracks are still comparatively narrow. Thus, on a clean disk, the NeXT might lay down a track like this: FF FF FF FF FF FF FF FF FF FF The NeXT has no problem reading this, but I suspect that the track is too narrow (and perhaps weak) for the Atari drive, which only correctly reads it sporadically. The worst case scenario could occur when fat tracks are written (as in formatting) on the Atari and overwritten by the NeXT. In this case, a single track might look like this: E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 FF FF FF FF FF FF FF FF FF FF This track would be correctly read by the NeXT, but the Atari drive head simultaneously reads both tracks with predictably poor results. This situation may apply to 720K IBM machines as well, but I don't have any experience there. For what it's worth, NeXT written disks read perfectly on a Compaq 386 with a 1.44 meg drive. Also, this problem could affect Atari machines differently; when I worked at an Atari service center, we counted _nine_ (!) different suppliers of floppy drives, with widely varying degrees of quality. >I would like to know if this is similar to others' experiences or if it >is peculiar to my system. Also is there a way to format an IBM >compatible disk using the NeXT? Use /NextAdmin/BuildDOS to format the disk. -sam (sam_s@NeXT.com) Opinions are not those of my employer, and could be totally wrong, besides...
pp39184@uxa.cso.uiuc.edu (Payman Parastaran) (03/25/91)
petcher@wuphys.wustl.edu (Donald N. Petcher) writes: >I myself have a NeXTstation, and an Atari ST, and when I format an IBM >compatible 720K MS-DOS disk on the Atari, the NeXT seems to have no >problem reading it. However, if I write anything on the disk with the >NeXT, and then try to get the Atari to read it, it always acts as if the >disk is damaged and the files are unreadable. I have had the same problem, but with swapping between a NeXT and a Mac SE/30 with a superdrive. If I go from the Mac to the NeXT, everything works just fine. The NeXT reads the MS-DOS disk without any complaints. But if I write a file on that same disk using the NeXT, I can't read it on the Mac. It tells me that the disk is damaged. What gives? -- ______________________________________________ Payman Parastaran / payman@uiuc.edu..............(217) 398-1452 / _______________________/_____________________________________________/__________