I thought I had still seen some WORM drives available today, usually used for
archiving purposes of medical records, etc. and they store about 1GB last time
I had one (was SCSI). however,
did some looking... apparently blu-ray has replaced the WORM drive (it is
actually WORM media). http://www.disc-group.com/technology/archive-requirements/
since it lasts 30 or 50 years (well, there's always archival DVD's from
mediasupply.com).
without cdrecord, that won't help.
I am just saying sector sizes fluctuate. it's a bad idea to rely on 512 byte
sectors or 4096-byte sectors or both because hard-coding is a Really Bad Idea
for a developer here and especially for an OS. I *think* a reason is, CHS
addressing limits this which is still in a lot of software and C compilers that
target DOS even though the drive itself uses 64-bit LBA now and CHS in the
BIOS is long dead, somehow, the legacy CHS has not been removed from DOS
software, and there is plenty out there which is now about to be rewritten to
handle 4096-byte sectors (sidekick, norton utilites, etc).
but I think we can move forward with what is available to be rewritten. you
search for 512 and change all the code that uses that to use a vasriable. in
fact, DJGPP makes provision for non-512-byte sector access, and my disk wipe
software written in DJGPP makes use of that (it's no longer released). coding
for such is quite possible, just requires using a variable instead of a
constant. it's not rocket science, folks.
with CHS there is an upper limit on the number of cylinders, heads, and spt and
probably track size too. drives simply keep getting bigger and bigger despite
people thinking "it can't get any bigger than what it is now" mentality, and
drive vendors just barrel through and increase the sector size to get around
the CHS limit I think. if all software addresses purely on LBA, there would be
less problems. however, the sector size has a fairly large upper limit. this
allows us to make good disk utilities, even stuff that works with GPT I should
think (if I can ever get a start and do diligence and read the agreement and
see if there is anything special I have to do to develop a program - I don't
think I have to pay $2500 membership to use UEFI+GPT).
there was an industry determination based on virtual memory page size being
4KiB, this being the most common disk activity at the time, that this
"swap/page" size should be used as the base sector size for optimal speed. RAM
is much less of a problem now and VM used much less (until sleep of course).
what MAY have to happen, is that software which expects 512-byte sectors may
need some sort of emulation (sound familiar?), like sidekick, norton utilities,
etc. and MAYBE, all of this is really handled by 512e (512-byte sector drive
emulation in 4k-sector drives). I think as long as you don't use physical
sector size, you will probably be OK for a while, maybe a long while.
if you must use physical sector sizes, then some sort of 512e emulation hotkey
would be nice that the user could press, or a program the person could run the
target program under, like
512e sidekick
or a hotkey TSR...
512e
^Ks
sidekick
^Ke
or something.
>________________________________
>
>From: Bertho Grandpied <[email protected]>
>To: [email protected]
>Sent: Thursday, January 2, 2014 3:40 AM
>Subject: Re: [Freedos-devel] 4, 096 byte sectors and DOSLFN, UIDE...question
>
>
>
>On Wed, 1 Jan 2014 23:01:35 -0800 (PST) Jim Michaels wrote :
>
>" ?hi... is there a chance it could work with any sector size,
>so that it doesn't have to be modified when things change
>again latrer? that could be extremely useful, since worm
>drives have 512, 1024 byte sectors, Advanced Format drives
>have 4096 byte sectors, and drive manufacturers are likely
>to increase this value as time goes on. so having something
>that can handle a variable number of sectors would be best. "
>
>It certainly can be made to work with alternate sector sizes,
>I do not have so exotic devices available to me for testing,
>however. As far as rotating disks are concerned, 4,096 bytes are
>the new standard se"ctor sizes, I don't think it likely to change in
>the foreseeable future. I've just looked up and found this blurb from IBM,
>what it describes is the kind of devices you had in mind - I guess :
>
>"Both WORM and erasable cartridges must have a sector size of 1024 bytes per
>sector for 1x, 2x, and 4x media. For 8x media, permanent WORM must have a
>sector size of 2048. Continuous composite write-once (CCW), WORM, and erasable
>media can either be 1024 or 2048 bytes per sector. 14x media is available in
>CCW and erasable in 2048 or 4096 bytes per sector. UDO media is available in
>8192 bytes per sector."
>
>Were you asking just in theory, or nave you got specific devices you'd
>want to test accessing in DOS ?
>I could send you a custom driver for a specified sector size. Note
>that your device should be partitionned a la conventional hard-disk (with MBR),
>the partition which you will access must be a "FAT" type and reside entirely
>within the first 16 million sectors (2^24) - this last restriction will be
>removed -
>and YOU must provide an "ASPI" DOS driver for your physical device !
>
>" this is a very nice Christmas present! cool! usb disks! I like this!"
>
>Me too :=)
>
>
>--
>Czerno
>
>
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