[EMAIL PROTECTED] wrote: > Every time I use it I get the reassuring answer that the hard drive does > not need a Defrag.
I think it has to be *really really* bad before you get told to defrag. I recently did lots of deletions and a general housekeep here at work and decided to defrag - it say that the disc was (somnething like) 96% fragmented but I didn't need to defrag. Go figure. I ignored the advice and set a defrag in motion overnight. Next morning, it was still running :o) > As far as Windows is concerned it is just one large file, so it cannot > itself be defragmented - which is what happens to the hard drive surface > area having gaps between areas of occupied data and areas not occupied > by data. I beg to differ (if I may). It makes no difference how big the file is (unless it is a single extent), it can be fragmented. A two extent file can have one extend in location A and another in location A+lots_of_displacement. That file is, technically, 50% fragmented and can be defragged. > The Defrag with DOS/Windows packs the data together, removing the > fragments that got separated to be a whole continuous area of data. This is correct. > Internally I don't know how the QXL.WIN holds its directions to > information. Yet it will not be affected by defragmenting. It can be. If the QXL.WIN file is spread of lots and lots of diosc area, in multiple fragments, then whenever the internal pointer says 'go here' that has to be transl;ated to a disc address physically on the drive platter(s). If you need to read lots of chuncks at 'random' locations then each read incurrs a rotational delay plus seek time plus latency period - which increase access times. If the chuncks of QXL.WIN you want are contiguous (or interleaved 'continuously') then there is a single 'mul;ti-block' read rather than lots of small reads. This incurs minimal rotational delay and latency or seek time and speeds up the read operation. > I guess someone can look all this up in the manuals ..... Someone had to learn this stuff for an exam some time back. Assuming the Oraganic RAM is still sort of working, the above should still be true. I don't think disc technology has progressed very far (other than in hardware) in the intervening years, however, I am always open to corrections - as those of you who have read my series on Assembly Language Programming will attest. :o) Cheers, Norman. _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
