[MacDV] Re: Formatting my hard drive

[Mark M. Florida]

On Dec 3, 2003, at 5:49 PM, Peter van der Linden wrote:

> I don't understand why you believe these system and application files 
> are somehow magically "not competing" with the scratch files just by 
> moving them into a separate partition.  Could you explain?   The 
> slowest part of disk access is head movement, followed by rotational 
> latency.  Moving things about on the same platter does nothing to 
> minimize either, and may conceivably make them both worse, no matter 
> how many partitions you have on one disk.

I don't think it's an issue of the speed of the drive mechanism as much 
as it is the system finding enough contiguous space to write a 
continuous data stream like video, audio, and even Photoshop scratch 
files to an extent.  Like you said, the slowest part of disk access is 
head movement, and that can definitely minimized by separating your 
media -- the head won't have to move if it doesn't run into a file in 
it's way while writing the video data stream...  I only suggested 
having 2 partitions on the system disk -- one for both OS and apps, and 
a second for media storage.  I'm not suggesting creating partitions for 
separating things like video, audio, renders, images, etc...  THAT 
would be a waste...

> You would have to move the files into a separate disk running under a 
> separate controller on a separate I/O bus to truly accomplish some 
> performance improvement.

Not so.  All ATA technologies used in G4s and G5s provide way more 
bandwidth than a single drive could use -- even writing to two drives 
in a RAID 0 on the same ATA bus will greatly increase throughput (not 
that editing DV would ever need that kind of throughput).  Although 
using two separate buses would in fact be faster just due to the 
overhead required to manage a task like that on the same bus.

But that's not even the issue here...  ugh.

> Try a benchmark of editing with everything in one partition vs. a 
> separate partition.  You may surprise yourself.

For short-term use there will probably not be much difference, 
especially regarding DV video, which is a fairly low-bandwidth stream.

The difference lies in LONG-TERM usage.

By keeping your apples in a different basket than your oranges, every 
time you add apples or oranges, they can be placed in their own baskets 
neatly.  And if you need an orange, you won't have to dig through your 
apples to find one.

By keeping your apps and OS on a separate partition, every time you 
install new software or an OS update, you don't have to worry as much 
about fragmentation of your system files or media files since they are 
on separate partitions.  Also, as your workflow permits, if you get to 
a point where you can copy all media to a separate partition, you can 
reformat the original partition and copy your media files back to it 
for a TRULY defragged drive.

> Partitioning originally had two main uses: 1.  to prevent the system 
> stopping when /tmp (or some other resource) filled up, and 2. to make 
> backups easier.  It was never a performance enhancing tool.  
> Fragmentation has not been a performance problem on modern filesystems 
> for at least a decade.

It sounds like you're looking at this from a UNIX/Linux perspective 
where the separate parts of the SYSTEM required their own partition to 
do their job...  While it is definitely true that the SYSTEM doesn't 
need separate partitions to work properly, it is much more efficient to 
keep your video and audio media on a SEPARATE, DEDICATED partition with 
merely a few hundred files vs. a few HUNDRED THOUSAND files...

I'm looking at this from the perspective of someone who has worked with 
digital video and print production for over 10 years...  Only recently 
have systems become fast enough to not worry *AS MUCH* about 
fragmentation -- but it's still a legitimate concern for video work 
where huge files are written and deleted in CONTINUOUS STREAMS, and low 
latency is CRITICAL for a glitch-free workflow.

> Partition all you like, but don't kid yourself its doing anything for 
> performance.

*TIME* will certainly tell...

- Mark F.