Low Level Format

From: Doc <doc_at_mdrconsult.com>
Date: Fri Aug 22 18:21:00 2003

Joe wrote:
> At 12:09 PM 8/21/03 -0400, you wrote:
>>If the LLF is not performed on IDE drives,
>>then I wonder wonder what Format does spend its time on?
> That's a good question. However there's a LOT of clusters on a modern HD
> and it has to create FAT entries for all of them (actually TWO FATs) plus
> create a directory. Perhaps it writes and verifies those areas of the drive
> but not the data area.
> But as Gene or Fred pointed out, a LLF format on the OLD MFM drives with
> only 100 or 200 Mb or so took 12 plus hours to run. Imagine what it take
> for a modern 80Gb drive! Yes, seek time has decreased but only about a
> factor of two (18ms to about 9ms). FYI I just installed an 80Gb drive
> night before last. It took well under an hour to partition AND HL format it.

   Building a MS-DOS FAT16 or FAT32 filesystem from Linux or
<name-your>BSD takes seconds on a hard disk partition, and Windows or
DOS have no problem with such a filesystem. I think DOS FORMAT just
needs to look busy. ;)

>>I mean, on floppies a HLF takes about a second.
> Then your system is a LOT faster than any I've seen. It takes at least a
> minute (ball park,I haven't timed it) on all that I've seen.

   Linux has two common tools for doing a high-level DOS format on
floppies - mformat and mkfs.msdos. Neither take more than 5 seconds to
operate. Usually more like 2.

   A full format on a floppy from Windows 98 on my laptop (the only
dual-boot machine I have) takes nearly 90 seconds, and renders the
computer basically useless while it's going on. From Linux, "fdformat",
which does an LLF and block-level verify on a floppy, *and* mformat or
mkfs.msdos, takes about 45 seconds total, and doesn't slow down system
response much at all.

   In short, I couldn't tell you why making a filesystem in DOS or
Windows occupies near-100% CPU for days. Any number of other operating
systems have proved it's not necessary.

Received on Fri Aug 22 2003 - 18:21:00 BST

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