[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

4979.0. "File Fragmentation questions ..." by MEALA::COLLINS (STEVE) Thu Aug 22 1991 05:17

    
     Has anyone used the disk fragmentation programs on ff519 ?
    
     There is one program called checkfrag wich will simply check
     file fragmentation on a device and another called opt which
     will also scan a disk for fragmentation defragment it.
    
     Checkfrag works for me and tells me that files on both my hard 
     disks are fragmented and also suprisingly that files copied
     to a ram disk are fragmented.
    
     I have been able to use opt to defrag the ram disk VD0 but it 
     won't work on my hard disks. It reboots the machine , even when
     just scanning for fragmentation.
    
     one thing that puzzles me is if I freshly format a hard disk 
     partition. Copy some files to rad , defragment them and copy
     them to the fresh partition the files end up fragmented as 
     before. Any one know why this should be ?
    
     I've found that fragmentation is dependant on the size of the 
     file , if it's around 1k bytes (I didn't determine the exact
     size) then it doesn't fragment. Could this be something to do 
     with FFS.
    
     
    
    
     Steve...
     
    
T.RTitleUserPersonal
Name
DateLines
4979.1AmigaDos is dirty on copiesSALEM::LEIMBERGERThu Aug 22 1991 06:1518
    I recently moved my files from an RZ23 to a RZ24. Prior to moving the
    files all the partitions on the RZ23 had been defragmented using 
    QuarterBack Tools. After the move QBT reported 1350 files fragmented
    out of 1790 . I think it did say there were two free sections of disk.
    I went out and defragmented the partitions on the RZ24. Now the RZ24
    was freshly formatted in AmigaDos, and the RZ23 was pretty clean. I
    don't know how the fragmentation is happening but I was dissappointed
    to say the least. I haven't bothered to restore a partition with
    QuarterBack yet, so I don't know how well the defragmentation holds up
    with backups. I would hope it keeps the files defragmented. Aside from
    defragmenting QBT will also make an effort to place your .info files
    on the disk for better workbench performance. I use some 700k+ files
    with imagine so I try to keep them defragmented as much as possible.
    	Aside from using QBT I never save data to the partitions that hold
    my OS, and Application software. It often takes a second longer to save
    data(specify a different partition) but then I figure it helps to keep
    the partition clean. 
    							bill
4979.2exVSSCAD::GATULISFrank Gatulis 226-6140Thu Aug 22 1991 12:3344
    re .-1
    
    Bill,
    
    I ran into some disappointments in the area of backup.  I "assumed"
    that the sequence of doing a Quarterback backup, deleting all files
    in the partition, and doing a Quarterback restore, would give me
    a dfragmented partition.  Wrong!  And the folks a Central Coast
    said this should work.
    
    I then did another variation of the experiment.  I first defragmented
    using QBTools (so I know my starting point).  Then I did the Backup,
    Delete, Restore operation and sure enough, QB tools says I'm fragmented
    all over the place. 
    
    I was disapointed and don't know what to conclude.  Central Coast
    initally said it would work.  Is it really fragmented or is there
    something funny in QBTools that makes it "think" it's fragmented.
    I've called a couple of times, but since Central Coast became part
    of New Horizons I've not been able to contact anyone that knows enough
    about this software to answer questions.
    
    Assuming that both Quarterback and QBTools are working correctly,
    I can only guess that the AmigaDOS I/O system does nothing in the
    way of disk organization to minimize fragmentation (even on an
    empty media you get it).
    
    I try to keep my partitions no more than 1/2 to 3/4 full and I can
    honestly say I don't notice any difference in performance whether
    they're defragmented or not.  I also believe that there are probably
    zillions of ways files can "technically" be fragmented and not be
    costing you performance, there are to many other considerations in 
    the system.  I wouldn't exactly call my A2000 a "balanced system"
    when it comes to performance.
    
    Frank
    
    
    
    
    
    
    
    
4979.3exGIDDAY::MORANThu Aug 22 1991 21:5916
    
    Recently I borrowed for the night an RZ23 and took it home. I usually
    only have a 42Meg 'Work' partition. I had defraged this partition using
    QBTools just a couple of nights ago. Just to play around I copied my
    Work partition to one of the empty ones on the RZ23 - reformated the
    42Meg partition - and copied the files back.
    
    Disk access was at least twice as quick, and that was after I had
    defraged the files!
    
    Does anyone have any techinal explanations on why the AmigaDos file
    system loves to fragment files or is it just lazy programming on
    Commodore's side ???
    
    Shaun.