jason@madnix.UUCP (Jason Blochowiak) (06/09/89)
In article <32248@apple.Apple.COM> dlyons@Apple.COM (David Lyons) writes: > [...] Another approach would be to do something similar >to what the Font Manager does with FONT.LISTS--keep a pre-built list of >the things & know when to rebuild it automatically, without opening any >of the files (just check for changes in name or last-mod date for all the >files in the directory). Is it safe &&/|| reasonable to check the modification date of the parent directory (to find out if anything's changed)? It would seem that this would be significantly quicker vs. file checking when there weren't any changes (which it's assumed would be most of the time). I was thinking about doing something like NCD for APW (NCD is one of Peter Norton's MS-DOS utilities that lets you change the current directory using a text representation of the directory tree on the disk - something like what Copy ][+ shows), and it'd be horrendously inefficient to re-read the entire disk's directories. So, "will it always be true" that checking a directory's modification date against something stored will guarantee that none of the children of that directory have been changed since the stored date? > --Dave Lyons, Apple Computer, Inc. | DAL Systems -- _______________________________________________________________________________ jason@madnix.UUCP, methinks. Formerly blochowi@garfield.cs.wisc.edu "It beats working" - Harrison Ford
dlyons@Apple.COM (David Lyons) (06/12/89)
In article <683@madnix.UUCP> jason@madnix.UUCP (Jason Blochowiak) writes: > Is it safe &&/|| reasonable to check the modification date of the >parent directory (to find out if anything's changed)? It would seem that >this would be significantly quicker vs. file checking when there weren't >any changes (which it's assumed would be most of the time). >[...] No, it isn't safe under all conditions. Although the ProDOS FST normally propogates the mod-dates back up the tree all the way to the volume directory under System Disk 5.0 (and up to the top subdirectory under 4.0, I *think*), ProDOS 8 (and ProDOS 16?) doesn't. Note that the mod-dates show up in the result of GET_DIR_ENTRY, so it isn't necessary to do a GET_FILE_INFO on each file. This makes things very reasonable if you need to see if a particular directory has changed. (If you need to do a whole disk, you still have a problem.) > jason@madnix.UUCP, methinks. Formerly blochowi@garfield.cs.wisc.edu > "It beats working" - Harrison Ford --Dave Lyons, Apple Computer, Inc. | DAL Systems AppleLink--Apple Edition: DAVE.LYONS | P.O. Box 875 AppleLink--Personal Edition: Dave Lyons | Cupertino, CA 95015-0875 GEnie: D.LYONS2 or DAVE.LYONS CompuServe: 72177,3233 Internet/BITNET: dlyons@apple.com UUCP: ...!ames!apple!dlyons My opinions are my own, not Apple's.
m.tiernan@pro-angmar.UUCP (Michael Tiernan) (06/14/89)
Network Comment: to #1289 by obsolete!dlyons%apple.com Dave, in your message, you point out that the ProDOS FST propagates the changed dates through the directory structure but ProDOS 8 doesn't. I thought (Note that I didn't say assume! :->) that it was the application's responsibility to perform the propagation under ProDOS 8? And as such, YES chcking the root directory for a change in Mod date is legal but NO it's a very foolish thing to assume that EVERYONE who has handled the ball won't drop it. << MCT >> BCS Apple/Boston Connection [MCT] (617) 893-5681 GEnie M.Tiernan AppleLinkPE M Tiernan BCS Net Michael Tiernan obsolete!pro-angmar!m.tiernan@bloom-beacon.mit.edu obsolete!pro-angmar!m.tiernan@bu-it.bu.edu pro-angmar!m.tiernan@obsolete.uucp m.tiernan@pro-angmar.cts.com
dlyons@Apple.COM (David Lyons) (06/16/89)
In article <8906150640.AA06515@obsolete.UUCP> m.tiernan@pro-angmar.UUCP (Michael Tiernan) writes: >Network Comment: to #1289 by obsolete!dlyons%apple.com > >Dave, in your message, you point out that the ProDOS FST propagates the >changed dates through the directory structure but ProDOS 8 doesn't. I thought >(Note that I didn't say assume! :->) that it was the application's >responsibility to perform the propagation under ProDOS 8? And as such, YES >chcking the root directory for a change in Mod date is legal but NO it's a >very foolish thing to assume that EVERYONE who has handled the ball won't drop >it. Root directories don't even *have* mod-dates under ProDOS 8, unfortunately. GET_FILE_INFO on a volume name always (as far as I've ever seen) returns zero for the mod-date. Right--many applications *don't* bother propogating mod-date changed back up the directory tree. (My own stuff doesn't even do it.) --Dave Lyons, Apple Computer, Inc. | DAL Systems AppleLink--Apple Edition: DAVE.LYONS | P.O. Box 875 AppleLink--Personal Edition: Dave Lyons | Cupertino, CA 95015-0875 GEnie: D.LYONS2 or DAVE.LYONS CompuServe: 72177,3233 Internet/BITNET: dlyons@apple.com UUCP: ...!ames!apple!dlyons My opinions are my own, not Apple's.