Re: Drive Geometry -- confusion.
On Wed, 29 Oct 2003 22:20, nw1 wrote: > FreeBSD 4.8-RELEASE-p13 > This document can also be viewed @ > https://69.3.136.141/freebsd/installation/geometry > > Install 4.8 from CD-rom > > Drive Geometry confusion. > My BIOS allows me a very limited amount of settings when it comes to an > HDD. The following are the only settings offered by my BIOS: > > Read Prefetch - [Disabled | Enabled] - set to (Disabled) > Disk Bios Translation - [LBA | CHS | Disabled] - set to (LBA) > Local Bus IDE Mode - [High Performance | Compatible] - set to (High > Performance) > > Size - 8455 MB --Auto-detected-- This is actually an 80GB HDD model: > WD800JB. (Unable to change the 'Size' setting.) > > The only other setting that could remotely be associated with any HDD's > installed would be the 'boot order' of the devices. > > ... sysinstall main menu | Custom | Partition : > > Here's where I'm confused; The following dialog message is printed: > > WARNING: A geometry of 155061/16/63 for ad0 is incorrect. Using a more > likely geometry. If this geometry is incorrect or you are unsure as to > whether or not it's correct, Please consult the Hardware Guide in the > Documentation submenu or use the (G)eometry command to change it now. > > Remember: you need to enter whatever your BIOS thinks the geometry is! For > IDE, it's what you were told in the BIOS setup. For SCSI, its the > translation mode your controller is using. Do NOT use a "physical > Geometry". > > ## With the above two (2) paragraphs having been said, All I have at this > point is the physical geometry given by the WD800JB specs --which the above > paragraphs are currently fobbing me to use. > > Lets press for OK and move further into this... > > We're in the FDISK Partition Editor where it states on the second line from > the top: DISK Geometry: 9729 cyls/255 heads/63 sectors = 156296385 sectors > (76316MB) > > If I understand correctly, the physical geometry of this WD800JB is: > > Cylinders = 16383 > Heads = 16 > Sectors/Track = 63 A simple calculation from these figures gives a total capacity of about 8.4Gb. In no way are these figures real (or even equivalent) for an 80Gb drive. The problem is that the hardware/software does not have the bit capacity to recognise more than 16383 cylinders. The 80Gb corresponds roughly with the 155061/16/63 figure. In fact modern drives at the disk hardware level expect simple absolute sector number for addressing not CHS, and in fact there may be different numbers of sectors to a track dependent on its diameter. So the 155061/16/63 figures are only some sort of equivalent CHS used in translating CHS addresses to absolute sector numbers. In principle you could pretend the CHS geometry was almost anything you want so long as it allows translation of hypothetical CHS addreses to real absolute sector addresses. The catch comes in the limitations of the bios/software/hardware registers to hold the CHS quantities. Using maxima for heads (255) and sectors (63) keeps the number of cylinders to a realisable value. Hence 9729/255/63 looks like the right choice. Malcolm Kay ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Drive Geometry -- confusion.
Jim, Thanks for that, but I'm no closer to understanding my initial questions as seen on or at; https://69.3.136.141/freebsd/installation/geometry Why does the installation forbid us to use the 'physical geometry? --I'm sure there's a valid reason, I'd like to hear it. in this instance, can someone explain what to do and, why? for future reference. - Original Message - From: "Jim" <[EMAIL PROTECTED]> To: "nw1" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Wednesday, October 29, 2003 8:46 AM Subject: RE: Drive Geometry -- confusion. > > > -Original Message- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of nw1 > > Sent: Wednesday, October 29, 2003 5:51 AM > > To: [EMAIL PROTECTED] > > Subject: Drive Geometry -- confusion. > > > > > > FreeBSD 4.8-RELEASE-p13 > > This document can also be viewed @ > > https://69.3.136.141/freebsd/installation/geometry > > > > Install 4.8 from CD-rom > > > > Drive Geometry confusion. ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: Drive Geometry -- confusion.
> -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of nw1 > Sent: Wednesday, October 29, 2003 5:51 AM > To: [EMAIL PROTECTED] > Subject: Drive Geometry -- confusion. > > > FreeBSD 4.8-RELEASE-p13 > This document can also be viewed @ > https://69.3.136.141/freebsd/installation/geometry > > Install 4.8 from CD-rom > > Drive Geometry confusion. > My BIOS allows me a very limited amount of settings when it comes > to an HDD. > The following are the only settings offered by my BIOS: > > Read Prefetch - [Disabled | Enabled] - set to (Disabled) > Disk Bios Translation - [LBA | CHS | Disabled] - set to (LBA) > Local Bus IDE Mode - [High Performance | Compatible] - set to > (High Performance) > > Size - 8455 MB --Auto-detected-- This is actually an 80GB HDD > model: WD800JB. > (Unable to change the 'Size' setting.) > > The only other setting that could remotely be associated with any HDD's > installed would be the 'boot order' of the devices. > > ... sysinstall main menu | Custom | Partition : > > Here's where I'm confused; The following dialog message is printed: > > WARNING: A geometry of 155061/16/63 for ad0 is incorrect. Using > a more likely > geometry. If this geometry is incorrect or you are unsure as to > whether or not > it's correct, Please consult the Hardware Guide in the > Documentation submenu or > use the (G)eometry command to change it now. > > Remember: you need to enter whatever your BIOS thinks the > geometry is! For IDE, > it's what you were told in the BIOS setup. For SCSI, its the > translation mode > your controller is using. Do NOT use a "physical Geometry". > > ## With the above two (2) paragraphs having been said, All I > have at this point > is the physical geometry given by the WD800JB specs --which the above > paragraphs are currently fobbing me to use. > > Lets press for OK and move further into this... > > We're in the FDISK Partition Editor where it states on the second > line from the > top: DISK Geometry: 9729 cyls/255 heads/63 sectors = 156296385 > sectors (76316MB) > > If I understand correctly, the physical geometry of this WD800JB is: > > Cylinders = 16383 > Heads = 16 > Sectors/Track = 63 > > As seen on/at: The Westerndigital.com site. > http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_ faqid=699&p_cr eated=1037217622 I'm inclined to use the above three (3) values, however, The above FreeBSD installation 'dialog' expressly *forbids the use of the physical geometry. Is this not confusing to you as well? Why does the installation forbid us to use the 'physical geometry? --I'm sure there's a valid reason, I'd like to hear it. Can someone explain what to do and, for future reference, <-- *why do that? As stated above; I'm confused. - All incoming attachments get deleted. Have a nice day. - ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]" This was a message from a little while ago that might shed some light: On Tue, 9 Sep 2003, at 12:17:54, Mark Terribile wrote: >>>> > Well, I've got my 120G disk up and running and > now I'd like to understand something odd. > > I went into /stand/sysinstall to put down the > partition and slice tables and the FS and found that > it determined the geometry (cyl/head/sectors) as > 15107/255/63 . Since it warned that the values must > match the BIOS values, I set them to the 59131/16/255 > that the BIOS reports. It rejected this entry and > went back to its own. I also tried the values > reported > by the ata driver on startup; these too were rejected. > > Since it's working (with about 117G -- that's > Gi_b_abytes) it must be OK (famous last words!) but > what's going on here? Why does it demand the values > reported by the BIOS if it will refuse them, and why > does the driver come up with another set of values, > also unacceptible to the disklabel/fdisk machinery? >>>> I expect that most people reading this are aware of some of the limitations of "BIOS" disk addressing, including the physical disk addresses in the disk partition table in the MBR (master bootstrap record) of bootable PC disk drives which allocates only 10 bits for the cylinder number, 8 bits for the head number, and 6 bits for the sector number. There is also a Fixed Disk "Drive Parameter Table" available through the traditional BIOS
Drive Geometry -- confusion.
FreeBSD 4.8-RELEASE-p13 This document can also be viewed @ https://69.3.136.141/freebsd/installation/geometry Install 4.8 from CD-rom Drive Geometry confusion. My BIOS allows me a very limited amount of settings when it comes to an HDD. The following are the only settings offered by my BIOS: Read Prefetch - [Disabled | Enabled] - set to (Disabled) Disk Bios Translation - [LBA | CHS | Disabled] - set to (LBA) Local Bus IDE Mode - [High Performance | Compatible] - set to (High Performance) Size - 8455 MB --Auto-detected-- This is actually an 80GB HDD model: WD800JB. (Unable to change the 'Size' setting.) The only other setting that could remotely be associated with any HDD's installed would be the 'boot order' of the devices. ... sysinstall main menu | Custom | Partition : Here's where I'm confused; The following dialog message is printed: WARNING: A geometry of 155061/16/63 for ad0 is incorrect. Using a more likely geometry. If this geometry is incorrect or you are unsure as to whether or not it's correct, Please consult the Hardware Guide in the Documentation submenu or use the (G)eometry command to change it now. Remember: you need to enter whatever your BIOS thinks the geometry is! For IDE, it's what you were told in the BIOS setup. For SCSI, its the translation mode your controller is using. Do NOT use a "physical Geometry". ## With the above two (2) paragraphs having been said, All I have at this point is the physical geometry given by the WD800JB specs --which the above paragraphs are currently fobbing me to use. Lets press for OK and move further into this... We're in the FDISK Partition Editor where it states on the second line from the top: DISK Geometry: 9729 cyls/255 heads/63 sectors = 156296385 sectors (76316MB) If I understand correctly, the physical geometry of this WD800JB is: Cylinders = 16383 Heads = 16 Sectors/Track = 63 As seen on/at: The Westerndigital.com site. http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=699&p_cr eated=1037217622 I'm inclined to use the above three (3) values, however, The above FreeBSD installation 'dialog' expressly *forbids the use of the physical geometry. Is this not confusing to you as well? Why does the installation forbid us to use the 'physical geometry? --I'm sure there's a valid reason, I'd like to hear it. Can someone explain what to do and, for future reference, <-- *why do that? As stated above; I'm confused. - All incoming attachments get deleted. Have a nice day. - ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
