fischer-michael@cs.yale.edu (Michael Fischer) (01/10/91)
In article <1991Jan9.180133.10001@uvm.edu> pegram@kira.UUCP (Robert B. Pegram) writes: >Um, I regularly have more than 113 files in a _SubDirectory_ the >problem only crops up with the _Root_ directory. It has to do with >the number of sectors reserved for the File Allocation Table. I >believe that MeSsDos floppies have fewer sectors reserved than >regularly formatted ST floppies (Note: the space set aside for the FAT >on floppies is configurable on several PD and shareware ST formatters, >hypercopy comes to mind as one). Also, this problem may not show up, >or may be at a much larger number of files for hard disk root >directories. Why subdirectories haven't got this problem, I don't >really know, it could be that they again have the problem with a >really *large* number of files. > >Maybe a quick Dos - Tos disk format refresher is in order? A Dos/Tos disk is divided up into several fixed-sized regions: boot sector, FAT (2 copies, actually), root directory, and data. The sizes of these regions are determined when the disk is formatted and can differ from disk to disk. The FAT must be big enough to hold the entries describing the allocation of clusters in the data region; beyond that, bigger isn't better. The root directory on a floppy is typically 7 sectors, which is big enough for 112 entries. On a hard disk, the root directory is often made considerably larger. Subdirectories are stored like files in the data region and can be any length. That's why the size restriction doesn't apply to them. -- ================================================== | Michael Fischer <fischer-michael@cs.yale.edu> | ==================================================
pegram@kira.UUCP (Robert B. Pegram) (01/11/91)
From article <27995@cs.yale.edu>, by fischer-michael@cs.yale.edu (Michael Fischer): I wrote: an incorrect description of why Dos/Tos floppies can only have 113 files in the root directory: >>Um, I regularly have more than 113 files in a _SubDirectory_ the >>problem only crops up with the _Root_ directory. ... mostly omitted, so I don't increase my embarassment 8-) 8-). ... >>Maybe a quick Dos - Tos disk format refresher is in order? Michael Fischer corrects and clarifies: > A Dos/Tos disk is divided up into several fixed-sized regions: boot > sector, FAT (2 copies, actually), root directory, and data. The sizes > of these regions are determined when the disk is formatted and can > differ from disk to disk. The FAT must be big enough to hold the > entries describing the allocation of clusters in the data region; > beyond that, bigger isn't better. The root directory on a floppy is > typically 7 sectors, which is big enough for 112 entries. On a hard > disk, the root directory is often made considerably larger. > Subdirectories are stored like files in the data region and can be any > length. That's why the size restriction doesn't apply to them. > > -- > ================================================== > | Michael Fischer <fischer-michael@cs.yale.edu> | > ================================================== Ah that's it, and it's worth repeating, clearly I should have talked about the size of the root directory rather than of the FAT. Hypercopy does allow you to format with user specified root directory sizes, helping the problem on floppies, as I mentioned in my earlier posting. Still, that leaves David Baggett's problem under Gulaam. Anybody know what gives with that shell? Bob Pegram pegram@griffin.uvm.edu or uunet!uvm-gen!pegram Hmmm, I gotta be more accurate or people will start putting ME in their kill files! 8-) RBPIII
GERLOFF@tubvm.cs.tu-berlin.de (Olaf Gerloff) (01/14/91)
In article <1991Jan9.180133.10001@uvm.edu>, pegram@kira.UUCP (Robert B. Pegram) says: > >Um, I regularly have more than 113 files in a _SubDirectory_ the >problem only crops up with the _Root_ directory. It has to do with >the number of sectors reserved for the File Allocation Table. I Hello Robert! You are nearly right. You can have 112 entrys in the root directory, because the formatters reserve normaly 7 sectors for the root directory on a floppy. This size is an entry in the bootsector. The number of sectors for the FATS has nothing to do with the number of files. It's size will be calculated so, that there is an entry for every cluster on the disk. As one can see the FAT size has nothing to do with the maximal number of files on the disk. Greetings, Olaf
ralph@laas.fr (Ralph P. Sobek) (01/15/91)
Wouldn't it be possible to FORMAT a floppy and initialize it with a bigger ROOT directory? That should be possible, shouldn't it? If I remember correctly, the root directory is defined in Sector 0. -- Ralph P. Sobek Disclaimer: The above ruminations are my own. ralph@laas.fr Addresses are ordered by importance. ralph@laas.uucp, or ...!uunet!laas!ralph If all else fails, try: sobek@eclair.Berkeley.EDU =============================================================================== Proud new owner of a Mega 4 ST. What should I do with my *small* SH204 drive?