Hugh, Consider that most current spec hard drives PATA and SATA tend to have 8, or 16Mb cache, and the ability to 'read-ahead' I.E. read an entire track into cache. The more data packed onto a track, the more benefit is gained from that ability.
This means that, if a file occupies a contiguous portion of the disk, then the 'track read' facility can read, and store - say 32Kb of data in 1 revolution of the drive, and will not need to reposition the heads and wait for the allocation unit ( 4KB perhaps) to come round to the heads for the next 7 read requests ( regardless of the rpm that's still only going to use slightly over 1/8th of the disk access time that would be required to read a fragmented version of the same file. And - you also save on the time needed to search the FAT, or MFT for those additional 7 allocation units, because with an unfragmented file, they all (usually) are in the same block of allocation entries. That situation will change slightly with SATA-II 'intelligent command queuing, but only for a system doing enough intermingled access requests to build a queue. Re the paging file Try comparing application performance with a contiguous, and then with a fragmented pagefile, when the system is actively paging in & out - 2 applications with ongoing pagefaults as each want more 'real memory' than is currently available. However - you can also speed up a system by simply removing redundant file entries - such as the thousands of zero length files that can be generated by IE in the InternetTemporaryStorage. As per my earlier waffle on planning and allocating appropriate groups of files to particular partitions - a well structured and setup system may not gain much benefit from defrag JimB ----- Original Message ----- From: "Hugh Gundersen" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, February 28, 2006 5:45 PM Subject: Re: SOFT: Diskeeper vs. XP defrag On Tue, 28 Feb 2006 11:17:35 -0600, you wrote: Apart from our off list chats I have read that in lab tests that defragging a disk does very little to improve the speed of an Hdd. Defragging the swap file also does very little in speed improvements. According to PC Pro and a couple of other tech mags - "it's nice to have things in a neat pile but if there is no logical reason then there is no real point" or words to that effect. After all we cannot open the Hdd and see the neat rows of data all lined up and if it doesn't improve anything then why do it. It might have done something in the long and distant past when computers ran at tortoise top speed and Hdds were worth a fortune for 4Mb and a Kings ransome for 25Mb. Sir Hugh of Bognor -- Remember. You may honestly believe that you understood everything you thought I said but what you thought you heard wasn't exactly what I said. [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] -- ---------------------------------------- To Change your email Address for this list, send the following message: CHANGE WIN-HOME your_old_address your_new_address to: [EMAIL PROTECTED] Note carefully that both old and new addresses are required. -- ---------------------------------------- To Change your email Address for this list, send the following message: CHANGE WIN-HOME your_old_address your_new_address to: [EMAIL PROTECTED] Note carefully that both old and new addresses are required.
