In a message dated 8/19/02 16:19:38, [EMAIL PROTECTED] writes:
>For those wondering what HFS+ is about, in terms of the way it conserves >space at least, here is a very simplistic example. > >Imagine you have four pigeon holes .... (snip, snip, snip, snip, snip ... dang, my scissors are getting dull .... whack, whack, whack) Grin, THAT was a simplistic example????? Holy dear lord Daniel, I drank two beers and smoked a pack of cigarettes before I got to the end of your posting! I must admit though, it was the most interesting explanation of block structure that I've ever seen to date. Although I don't want to step on Daniel's toes, much less stomp all over his good intentions, perhaps I can offer a different explanation of this block structure business...... Prior to OS 8.1 and sometime after OS 4 or 6 (I can't remember), Apple used a file system called Hierarchical File System (AKA: HFS or Mac OS Standard). What this did was to allow for no more than 65,000-odd (do we REALLY need the exact number?) blocks in a partition. Most people back then only had their hard drives set up as one partition so this "limitation" applied to their entire hard drive (but more about this later). Of course, "back then" this wasn't considered a limitation because hard drives weren't very big and one didn't see too many drives that were over 2 or 3 gigabytes. However, hardware technology started to advance and we began seeing 4, 6, 9, 15, 20, etc., gigabyte hard drives hit the market. Unfortunately, this limitation of 65,000-odd blocks still applied to these larger drives and all of a sudden people with these larger hard drives were noticing that what was once a rather small file on a smaller drive became a much larger file on these large hard drives. And they were right; a one sentence Simple Text file took up a lot more room on a 27GB drive than on a 2GB drive. Well, think about it ---- if you divide 27GB into 65,000, that number is a lot bigger than if you divide 2GB into 65,000. OK, so a lot of us got around this 65,000-odd limitation by partitioning our drives (this will be the prior reference to "more about this later"). Why? Because under Apple's OS, each partition is treated as a separate drive and therefore the 65,000-odd block limitation only pertained to the partition (and not to the physical drive). So we could take, say, an 8GB drive and make it look like four 2GB drives. So why would Apple need to change this 65,000-odd limitation if Users could get around it with partitioning their hard drives? Well, add a few 20GB hard drives to your computer and try dealing with 10 to 20 partitions and you will understand why this block structure wasn't working. Besides that, files were becoming massive and as we all know, 1 to 2 Gig files have become as common as flies. What really went down was that Users were getting mad that Apple's block structure was inefficient; that there was too much wasted space. And Apple changed in response to all the irate users; Apple introduced HFS+ (AKA: Hierarchical File System Plus or Mac OS Extended). HFS+ increased the potential number of blocks to somewhere in the billions (or so I'm told). OK well think about that ------ if you divide 27GB into "the billions", that number is a lot smaller than if divide 27GB into 65,000. There is a catch if one converts to the HFS+ file format though. To my understanding, no OS prior to 8.1 can read HFS+ file formats. That doesn't mean that the reverse is true; I'm running both OS 9.0 and OS 7.6 and all my files are non-HFS+ files. I should also say that I'm smack dab right in the middle of a massive conversion and although I am running both of these OS versions, I would NEVER recommend it. All the same, I'd be remiss in not pointing out that these two particular versions of OS can live in harmony. I don't have a clue as to what OS 9.1 would do with these files though. OK Daniel, I drank a few more beers and smoked another pack of cigarettes while I was composing this response but I don't think that I got any closer to providing a succinct answer than you did. So I'm thinking that perhaps your approach to the answer was just fine after all. I'm not sure why I'm even bothering to post this response other than if I don't, I've wasted my entire afternoon talking to myself (again). Will this insanity never stop? Linda -- StarMax is sponsored by <http://lowendmac.com/> and... / Buy books, CDs, videos, and more from Amazon.com \ / <http://www.amazon.com/exec/obidos/redirect-home/lowendmac> \ Support Low End Mac <http://lowendmac.com/lists/support.html> StarMax list info: <http://lowendmac.com/lists/starmax.html> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/starmax%40mail.maclaunch.com/> Using a Macintosh? Get free email and more at Applelinks! <http://www.applelinks.com>
