[P1] To partition or not

[Joost van de Griek]

On 2003-06-05 03:41, Charles Broderick wrote:

> On 6/4/03 12:03 AM, "iBook List" <ibook at lists.themacintoshguy.com> wrote:
> 
>> It's not enough to matter to me when I've got 40 gigs, luckily.  And back in
>> the HFS days of OS 9, you'd actually save space when you had partitions.
>> There's a maximum sector (or some such) number, so a file that's 1k might
>> take 153k (the smallest unit HFS would handle on a drive of arbitrarily large
>> size)
> 
> 
> I am amazed at the useless knowledge I can remember (as opposed to the
> important stuff I find so easy to forget).
> 
> Back in the day of 16 bit addressing, the most addresses you could address was
> 65535 (2 to the 16th power, minus one 'cuz computers start counting from 0).

Almost, but not quite.

16-bit addressing does give you 65536 addresses. Computers do indeed start
counting at 0, so that means you have addresses 0 through 65535.

> So no matter how big the hard drive was, you could only have 65535 files
> on it. When your hard drive was formatted, the Mac would simply take the
> size of the hard drive and divide it by 65535, and that was the size of each
> sector.
> 
> On a 250 MB hard drive, this was no big deal--each sector is about 4k big.
> If your file is 4k, it takes up 1 sector, if it is 12 it takes up 3, and if
> it is 13k it takes up 4.
> 
> The problem was with larger drives, for instance a 1 gig drive. 1 gig is
> actually 1024 * 1024 (2 to the 10th power) kilobytes, which is 1,048,576 kb.
> Divide that by 65535 and you get 16k per sector. So your 4k file would
> actually occupy 1 16k sector, your 12k file would take up 1 sector, and a
> 17k file would take up 32k (2 sectors).

<http://docs.info.apple.com/article.html?artnum=8647>

> Back in the day when MS word files used to be less than 1MB, (usually only
> 4k or 7k), this would waste a lot of space! So, people would partition
> larger drives to be able to recover some of that valuable space.
> 
> Nowadays, you certainly don't need to partition for this reason (I think
> they have 64-bit addressing and can address terabytes of info).

<http://docs.info.apple.com/article.html?artnum=24601>

> I find it conventient to have different operating systems on different
> partitions--OS X on one and OS 9 on another, with Linux on even yet another.
> You can change operating systems on one partition without affecting another.

Linux must be installed on a different partition, because it uses a
different file system.

OS X and OS 9, however, don't bite each other; they will not harm one
another by being on the same partition. Of course a user in one OS can hose
the installation of the other, but partitioning doesn't prevent that.

,xtG
.tsooJ
-- 
who | grep -i blonde | date
cd $HOME; unzip; touch; strip; finger
mount; gasp; yes; uptime; umount
sleep
-- 
Joost van de Griek
<http://www.jvdg.net/>