News Archive for: 8/17/2005 Wednesday's News |
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|Notes on Drive Free Space and Fragmentation|
|(from a reader mail - English isn't his native language so in some cases I've edited to help a bit)
even if pather / tiger do their best to avoid file fragmentation or
defrag (with a lot of restrictions) files by itself,
a look on your file- freespace fragmentation may help, to (determine causes of low) hd and system performance.
Since i uploaded my (sure not very well looking - don't hurt me apple
fans ;) ShowvolumeFragmentation freeware tool, i got a lot
of user feedback and some screenshots (with data my tool generates). Now i got a really high fragmentated situation on an 80GB HD. 10 GB were free. Sound not too bad, or ?
But it was very bad:
The 10 GB free isn't usable free, which means it's split
into near unusable pieces < 1 MB (down to 4 KB). 5 GB of the 10 GB free. The other 5 GB are between 1 and 10 MB.
With such an freespace situation, its impossible to avoid file
fragmentation (at file creation time) or do autodefrag (<20 MB, and
some other restrictions !!).
The example (orig. user screenshoot of sfv data) shows:
incredible fragmented Spamsieve History file : 1131 fragments , 130
MB size bad: also the swapfile (virtual memory) is fragmented into > 200 frags.
All that, happended , even with 10 GB of 80 GB free.
Maybe some other users have same situation (most will have less
fragmentation) ? An eye on that may help.
Here the screenshots using SVF before using CCC and after using CCC (clone to external HD; erase old, clone back).
SVF (ShowVolumeFragmentation) is availabe at
BEST information about HFS+ and framentation by the author of
hfsdebug (which my Tools uses).
(perhaps you remember me from the Powerlogix CPU Director
voodoo - ;)
Another reader replied to this post:
Hi Mike, He's right about this. We just had a long discussion about this at my
last usergroup meeting. http://www.metromac.org/
What I try to explain to people is that OS X will defrag files smaller
than 20MB. If you have a disk with many larger files, you could have a
problem. If a large PS file is scattered around the disk, it won't be
defragged. If you don't have enough free disk space, the process may
not work at all. You will only know this if you look at the log files.
Recopying files to another partition or disk will often solve the
problem, as you can then erase the files on the original disk and copy
them back if you have enough contiguous space for them after you have
defragged the partition. (or wiped it clean) CarbonCopyCloner is perfect for this purpose if you use it to clone a disk or partition.
10GB seems to be a lot of space, but it might not be. If the partition
has no booted OS, it needs less free space. But the OS only defrags the
main drive at this time. Other drives are on their own.
Some 3rd party utilities include an OS X defragger, but some have reported serious problems at times doing that. (See past reports from users of Drive Genius and Techtool Pro)
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|G5 owner report on problems if both Canon GL2 + FW Drives connected|
|(Updated for more comments on this issue)
Just purchased a new dual 2.7GHz G5. Problem started when I plugged the Canon GL2 into the front firewire port. However, after several
installs and being told by my local apple store that it is a software
problem I came to realize that the camera works fine if there is no
external drive connected.
I have a new 500 GB OWC elite AL and a 500 gig lacie big disk. Both interfere with the computer/camcorder interaction. Things seem to work fine if they are ejected/unplugged and I reboot. Any body else experience this?
I asked him if the problem was performance related (slow) or is it just not recognized? (Even the iSight has been reported to cause some performance problems if used simul. with other FW devices.)
Some other reader's replied to this post:
This is a followup to the fellow who reported the problem with having
a GL2 and a FW hard drive on a G5.
The problem seems to have existed since the original G5 dual 2.0 and
the Canon GL1, and (apparently) never fixed. I've heard that the XL1
also has the issue, so it seems consistent with Canon's higher end
cameras but I have no verification of this myself.
I've had the same problem on both an old G5 dual 2.0 and a dual
2.5: having both the GL2 (or 1) on the same FW bus as a FW HD causes
the Mac to not interact with the camera properly. I've only tested
with OWC FW800 drives, so I don't know if it's universal to all FW
drives (but I have read on CreativeCow forums about similar issues,
so it seems not to be unique).
You can't capture or export to the camera with Final Cut or iMovie at all (it's been a while since I bothered to try it, but I believe Final Cut just does a beachball
when you try a log and capture; unplugging the camera is required to
The only consistent workable solution I've found is to buy
a PCI Firewire card and keep the camera isolated on its own bus, which is
what I am doing at our office. It's sucks having to tie up a PCI-X
slot for s a workaround, but at least it works.
Jee H. L.
Mike Mihalik of Lacie wrote:
This is a rather old problem. Many posts on this at Apple Discussion forums.
Most Canon camcorders cannot tolerate other FireWire devices when connected
to the same FireWire bus. Problem is more prevalent with FW800 devices and
interfaces. This problem may also occur with some other audio and DV FireWire devices.
Why is this a problem: the 1394 devices with the problem expect to be the
only FireWire traffic on the bus; switching the speed down to S100.
There is no firmware fix.
Also, since all the built-in ports share the same FireWire bus (essentially
a hub), it doesn't matter how the FireWire devices are connected. So even a
separate hub will not fix the situation.
- add a second FireWire bus to the computer, using a PC Card if a laptop, or
a PCI card if a PowerMac.
I've added this to the previous page of G5 owner reports on FW and USB devices. (Which has reports on FW PCI cards, warnings on some model of Hubs and also a past problem report from a Canon GL2 owner I'd forgotten about.)
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|CDRW/CD/DVD/Hard Drive/Storage Compatibility Database Update Listing|
|The Drive Compatibility Database had 9 new reports added. (Entries today are added the next newsday morning.) The database includes reports on CDRWs, Combo DVD-CDRW, DVD-ROM, DVD Burners, Hard Drives and Removables (tape drive, ORB, ZIP, MO drives, NAS, CF/Smartmedia readers, etc.) in all interface types (IDE, IDE RAID cards, SATA, Firewire, SCSI, USB, adapters). Current total - 15,005 reports. (searching by drive type/brand, mac model etc. listed below will show the full reports, most recent first - does not include updates to previous reports) iApps burn support mentioned in reports unless otherwise noted.
Combo DVD(ROM) -CDR Drives:
- Exp. Bay Teac DW-224E-A in (Pismo) Powerbook G3 2000 (OS X 10.4)
(Systems page, Powerbook section has articles from 2001 on expansion bay combo drive installs/swaps.)
DVD+R/RW + DVD-R/RW Drives:
- IDE Pioneer DVR-110D in G5 Tower (OS X 10.4)
(noted using Patchburn 4, although tiger had basic iApps burn support without it.)
- IDE Pioneer DVR-K05/SP in iMac G5 (OS X 10.4)
- IDE Sony DRU-800A in G4/AGP (OS X 10.4)
(noted using Patchburn 4. Illustrated CD drive install guide here covers G4 towers up to the Digital Audio Model, Beige G3 MT and B&W G3 Macs)
- IDE Maxtor 60GB in G4/AGP (OS X 10.4)
(Illustrated guide to adding a 2nd HD here in B&W G3 rev2 and G4 towers up to the QuickSilver models. IDE articles page RAID section has an illustrated guide for adding 2 more drives in the side bays and IDE PCI controller card)
- IDE Maxtor DiamondMax Plus8 40GB in G4/AGP (OS X 10.4)
- IDE Toshiba MK4026GAX 40GB in PowerBook G4 (OS X 10.4)
(PowerBook G4 Ti 15in. LCD illustrated Hard Drive install guide here
PB G4 15in (Aluminum) Disassembly guide here.
Powerbook G4 12in LCD illustrated Hard Drive install guide here
FAQ's Powerbook section has links to other model guides.)
- USB SanDisk Cruzer Mini 128MB used w/G4 AGP (OS X 10.4)
- USB PNY Reader/Writer used w/G4 AGP (OS X 10.4)
You can find full owner reports (latest shown first) by searching the database by drive/brand/interface/mac models (the latest reports are shown first in searches).
For guides to installing CD/CDRW/DVD drives or Hard drives in many mac models, see the IDE Articles page. The Firewire articles page also has guides on case kits, installing drives, etc.
If you've added a IDE, SCSI, Firewire or USB hard drive, CDRW, tape drive, etc. make sure you add a report to the database. (If you post an updated entry - make sure you use the same name, etc. as you did before so I can find your past entry. Thanks.)
(Incomplete entries are deleted. Do not post questions in the database, it's for drive reports not questions on what drive to buy - for that try searching the database for reports from owners of your mac model on the drive type/brand/interface, etc. you're interested in.)
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