Date: Fri, 26 Jan 2024 10:45:21 -0700 From: Warner Losh <imp@bsdimp.com> To: "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net> Cc: Ed Maste <emaste@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Removing fdisk and bsdlabel (legacy partition tools) Message-ID: <CANCZdfpNNbFnjk59-aZWJt7YQuxuH%2BY8cx=kz5z828-4vWpXsg@mail.gmail.com> In-Reply-To: <202401261617.40QGHH8e006266@gndrsh.dnsmgr.net> References: <CANCZdfp9a0SoZARRAj=6%2BnVAKHXrFcELWd6G9zxL0gVGr=x2Rg@mail.gmail.com> <202401261617.40QGHH8e006266@gndrsh.dnsmgr.net>
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[-- Attachment #1 --] On Fri, Jan 26, 2024 at 9:17 AM Rodney W. Grimes < freebsd-rwg@gndrsh.dnsmgr.net> wrote: > [ Charset UTF-8 unsupported, converting... ] > > On Thu, Jan 25, 2024, 10:49?AM Rodney W. Grimes < > > freebsd-rwg@gndrsh.dnsmgr.net> wrote: > > > > > > On Thu, Jan 25, 2024, 9:11?AM Ed Maste <emaste@freebsd.org> wrote: > > > > > > > > > On Thu, 25 Jan 2024 at 11:00, Rodney W. Grimes > > > > > <freebsd-rwg@gndrsh.dnsmgr.net> wrote: > > > > > > > > > > > > > These will need to be addressed before actually removing any of > > > these > > > > > > > binaries, of course. > > > > > > > > > > > > You seem to have missed /rescue. Now think about that long > > > > > > and hard, these tools classified as so important that they > > > > > > are part of /rescue. Again I can not stress enough how often > > > > > > I turn to these tools in a repair mode situation. > > > > > > > > > > I haven't missed rescue, it is included in the work in progress I > > > > > mentioned. Note that rescue has included gpart since 2007. > > > > > > > > > > > > > What can fdisk and/or disklabel repair that gpart can't? > > > > > > As far as I know there is no way in gpart to get to the > > > MBR cyl/hd/sec values, you can only get to the LBA start > > > and end values: > > > > > > > In the last 20 years when have you needed this? > > Last week, and probably about every other month for the last > 30 years. > What. specifically did you need to change, for what hardware, etc? > > > > LBA start/end is all that's relevant these days. The CHS values are > > completely ignored > > by FreeBSD. We use packet mode in the boot loader since about Pentium > 150MHz > > or so. > > WORLD != FreeBSD, please STOP trying to assume that the users OF FreeBSD > are ONLY using FreeBSD!!!! > Yes. And the world stopped using them too around that time, give or take 5 years. > > > > I did have to change these back in the day when we inferred what the CHS > > geometry > > was from the drive by looking at the MBR's partitions that you knew > > (assumed really) > > started on a cylinder value. This hasn't mattered in FreeBSD since sos > > rewrote ata > > the second time. DOS had to do these things because old-school MFM, RLL, > etc > > disks couldn't return their CHS, so DOS had to enshrine them in the MBR > to > > get > > a hint (or have the drive type BIOS to just know). Since we use LBA > > exclusively, > > none of this matter to FreeBSD. > > WORLD != FreeBSD, and weither you like it or not your BIOS and CSM > and UEFI are PROPBABLY reading those values and might even do a > nice divide by zero for you should you write 0 in them. > Maybe rather than using all caps you could give a specific example. I've not had to help anybody with CHS values in maybe 15 years, and even then it was rare. In the prior 10 years to that I went from shipping product where CHS had to be right, to shipping product where it didn't matter at all on a set of SBCs that were lagging the industry by 5 years. Also, UEFI doesn't care: It has no CHS APIs. It's all LBA. The only places in the standard where 'Cylinder' is mentioned is the (now obsolete) name for fields in a ATA packet that now mean different parts of the LBA for modern commands. > > > > I've certainly never needed to tweak these in single user mode on an > > emergency > > basis. Why? Because you can't get to single user mode because the kernel > > won't > > even load if you have these wrong. So either you are booting some rescue > > disk > > to fix that (in which case you can craft it for your special > environment)., > > or you are > > rescue disk == any FreeBSD install media from the last 20 years. > your REALLY stuck in a small box Warner, please think outside > that box. You keep repeating FreeBSD FreeBSD FreeBSD, I have to > inform you many of us who USE FreeBSD also USE other stuff, but > we prefer to have FreeBSD be our goto system for this type of work. > Yes. I understand that. And with the packages installed, you still can do that. > > creating a special thing in multi-user, so you can install For all these > > use cases, fdisk > > as a port is fine. > > I really do not want to have to maintain my own distribution. > And the project can no longer support programs that have buffer overflows and other dangerous behavior when presented with untrusted information from the disks that matters only to a few users. > > > > sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD) > > > start 63, size 8388513 (4095 Meg), flag 80 (active) > > > beg: cyl 0/ head 1/ sector 1; > > > end: cyl 1023/ head 15/ sector 63 > > > > > > gpart show ada0 > > > => 63 8388545 ada0 MBR (4.0G) > > > 63 8388513 1 freebsd [active] (4.0G) > > > 8388576 32 - free - (16K) > > > > > > Now I have learned that gpart backup/restore CAN get me > > > at least basic bsdlabel -e function, but again it has > > > no access to all the stuff stored that showsup with > > > bsdlabel -A. Which this is now the third time I have > > > asked "how do I do bsdlabel -A -e with gpart"? One > > > person at least answered that with: > > > gpart backup GEOM >backup > > > vi backup > > > gpart restore GEOM > > > > > > > OK Let's look at these extra fields: > > > > # /dev/md0: > > type: unknown > > disk: amnesiac > > label: > > flags: > > bytes/sector: 512 > > sectors/track: 63 > > tracks/cylinder: 255 > > sectors/cylinder: 16065 > > cylinders: 130 > > sectors/unit: 2097152 > > rpm: 3600 > > interleave: 1 > > trackskew: 0 > > cylinderskew: 0 > > headswitch: 0 # milliseconds > > track-to-track seek: 0 # milliseconds > > drivedata: 0 > > > > type isn't used at all in FreeBSD. > > disk is for /etc/disktab, something we've not really needed since > FreeBSD 3 > > or so. > > label can be set with gpart add/modify -l. > > I've never used flags. Can't speak to that. > > bytes/sector: This is a physical property of the drive, not the label. > You > > can find it with gpart list: > > % gpart list md0 > > .... > > Consumers: > > 1. Name: md0 > > Mediasize: 1073741824 (1.0G) > > Sectorsize: 512 > > The rest of this/that are reported or you can do math: > > fwheads: 255 <- tracks/cylinder > > fwsectors: 63 <-- sectors/track > > last: 2097151 <-- sectors/unit - 1 > > now, cylenders and sectors/cylinder you can compute. geom does this for > > reading/writing disk labels. > > rpm is hard coded to 3600 these days. FreeBSD doesn't care. > > The rest are for interleaving, which FreeBSD doesn't do, so we don't > care. > > > > So you can influence the values, but they aren't used for anything by > > FreeBSD > > that matters. > > > > What if you need them for something else? Then just use the disklabel > port. > > You'll never need to hack them tn single user mode, so you can use the > port > > for all use cases. > > Booting a FreeBSD install image is the use case, you seem to not > realize people do use that for "RESCUE". FreeBSD 14 CD images will exist online for ~forever. Warner [-- Attachment #2 --] <div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jan 26, 2024 at 9:17 AM Rodney W. Grimes <<a href="mailto:freebsd-rwg@gndrsh.dnsmgr.net">freebsd-rwg@gndrsh.dnsmgr.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">[ Charset UTF-8 unsupported, converting... ]<br> > On Thu, Jan 25, 2024, 10:49?AM Rodney W. Grimes <<br> > <a href="mailto:freebsd-rwg@gndrsh.dnsmgr.net" target="_blank">freebsd-rwg@gndrsh.dnsmgr.net</a>> wrote:<br> > <br> > > > On Thu, Jan 25, 2024, 9:11?AM Ed Maste <<a href="mailto:emaste@freebsd.org" target="_blank">emaste@freebsd.org</a>> wrote:<br> > > ><br> > > > > On Thu, 25 Jan 2024 at 11:00, Rodney W. Grimes<br> > > > > <<a href="mailto:freebsd-rwg@gndrsh.dnsmgr.net" target="_blank">freebsd-rwg@gndrsh.dnsmgr.net</a>> wrote:<br> > > > > ><br> > > > > > > These will need to be addressed before actually removing any of<br> > > these<br> > > > > > > binaries, of course.<br> > > > > ><br> > > > > > You seem to have missed /rescue. Now think about that long<br> > > > > > and hard, these tools classified as so important that they<br> > > > > > are part of /rescue. Again I can not stress enough how often<br> > > > > > I turn to these tools in a repair mode situation.<br> > > > ><br> > > > > I haven't missed rescue, it is included in the work in progress I<br> > > > > mentioned. Note that rescue has included gpart since 2007.<br> > > > ><br> > > ><br> > > > What can fdisk and/or disklabel repair that gpart can't?<br> > ><br> > > As far as I know there is no way in gpart to get to the<br> > > MBR cyl/hd/sec values, you can only get to the LBA start<br> > > and end values:<br> > ><br> > <br> > In the last 20 years when have you needed this?<br> <br> Last week, and probably about every other month for the last<br> 30 years.<br></blockquote><div><br></div><div>What. specifically did you need to change, for what hardware, etc?</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> > <br> > LBA start/end is all that's relevant these days. The CHS values are<br> > completely ignored<br> > by FreeBSD. We use packet mode in the boot loader since about Pentium 150MHz<br> > or so.<br> <br> WORLD != FreeBSD, please STOP trying to assume that the users OF FreeBSD<br> are ONLY using FreeBSD!!!!<br></blockquote><div><br></div><div>Yes. And the world stopped using them too around that time, give or take 5 years.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> > <br> > I did have to change these back in the day when we inferred what the CHS<br> > geometry<br> > was from the drive by looking at the MBR's partitions that you knew<br> > (assumed really)<br> > started on a cylinder value. This hasn't mattered in FreeBSD since sos<br> > rewrote ata<br> > the second time. DOS had to do these things because old-school MFM, RLL, etc<br> > disks couldn't return their CHS, so DOS had to enshrine them in the MBR to<br> > get<br> > a hint (or have the drive type BIOS to just know). Since we use LBA<br> > exclusively,<br> > none of this matter to FreeBSD.<br> <br> WORLD != FreeBSD, and weither you like it or not your BIOS and CSM<br> and UEFI are PROPBABLY reading those values and might even do a<br> nice divide by zero for you should you write 0 in them.<br></blockquote><div><br></div><div>Maybe rather than using all caps you could give a specific example. I've</div><div>not had to help anybody with CHS values in maybe 15 years, and even</div><div>then it was rare. In the prior 10 years to that I went from shipping product</div><div>where CHS had to be right, to shipping product where it didn't matter at</div><div>all on a set of SBCs that were lagging the industry by 5 years.</div><div><br></div><div>Also, UEFI doesn't care: It has no CHS APIs. It's all LBA. The only places in the</div><div>standard where 'Cylinder' is mentioned is the (now obsolete) name for fields in</div><div>a ATA packet that now mean different parts of the LBA for modern commands.</div><div> <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> > <br> > I've certainly never needed to tweak these in single user mode on an<br> > emergency<br> > basis. Why? Because you can't get to single user mode because the kernel<br> > won't<br> > even load if you have these wrong. So either you are booting some rescue<br> > disk<br> > to fix that (in which case you can craft it for your special environment).,<br> > or you are<br> <br> rescue disk == any FreeBSD install media from the last 20 years.<br> your REALLY stuck in a small box Warner, please think outside<br> that box. You keep repeating FreeBSD FreeBSD FreeBSD, I have to<br> inform you many of us who USE FreeBSD also USE other stuff, but<br> we prefer to have FreeBSD be our goto system for this type of work.<br></blockquote><div><br></div><div>Yes. I understand that. And with the packages installed, you still can</div><div>do that.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> > creating a special thing in multi-user, so you can install For all these<br> > use cases, fdisk<br> > as a port is fine.<br> <br> I really do not want to have to maintain my own distribution.<br></blockquote><div><br></div><div>And the project can no longer support programs that have buffer overflows</div><div>and other dangerous behavior when presented with untrusted information</div><div>from the disks that matters only to a few users.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> > <br> > sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)<br> > > start 63, size 8388513 (4095 Meg), flag 80 (active)<br> > > beg: cyl 0/ head 1/ sector 1;<br> > > end: cyl 1023/ head 15/ sector 63<br> > ><br> > > gpart show ada0<br> > > => 63 8388545 ada0 MBR (4.0G)<br> > > 63 8388513 1 freebsd [active] (4.0G)<br> > > 8388576 32 - free - (16K)<br> > ><br> > > Now I have learned that gpart backup/restore CAN get me<br> > > at least basic bsdlabel -e function, but again it has<br> > > no access to all the stuff stored that showsup with<br> > > bsdlabel -A. Which this is now the third time I have<br> > > asked "how do I do bsdlabel -A -e with gpart"? One<br> > > person at least answered that with:<br> > > gpart backup GEOM >backup<br> > > vi backup<br> > > gpart restore GEOM<br> > ><br> > <br> > OK Let's look at these extra fields:<br> > <br> > # /dev/md0:<br> > type: unknown<br> > disk: amnesiac<br> > label:<br> > flags:<br> > bytes/sector: 512<br> > sectors/track: 63<br> > tracks/cylinder: 255<br> > sectors/cylinder: 16065<br> > cylinders: 130<br> > sectors/unit: 2097152<br> > rpm: 3600<br> > interleave: 1<br> > trackskew: 0<br> > cylinderskew: 0<br> > headswitch: 0 # milliseconds<br> > track-to-track seek: 0 # milliseconds<br> > drivedata: 0<br> > <br> > type isn't used at all in FreeBSD.<br> > disk is for /etc/disktab, something we've not really needed since FreeBSD 3<br> > or so.<br> > label can be set with gpart add/modify -l.<br> > I've never used flags. Can't speak to that.<br> > bytes/sector: This is a physical property of the drive, not the label. You<br> > can find it with gpart list:<br> > % gpart list md0<br> > ....<br> > Consumers:<br> > 1. Name: md0<br> > Mediasize: 1073741824 (1.0G)<br> > Sectorsize: 512<br> > The rest of this/that are reported or you can do math:<br> > fwheads: 255 <- tracks/cylinder<br> > fwsectors: 63 <-- sectors/track<br> > last: 2097151 <-- sectors/unit - 1<br> > now, cylenders and sectors/cylinder you can compute. geom does this for<br> > reading/writing disk labels.<br> > rpm is hard coded to 3600 these days. FreeBSD doesn't care.<br> > The rest are for interleaving, which FreeBSD doesn't do, so we don't care.<br> > <br> > So you can influence the values, but they aren't used for anything by<br> > FreeBSD<br> > that matters.<br> > <br> > What if you need them for something else? Then just use the disklabel port.<br> > You'll never need to hack them tn single user mode, so you can use the port<br> > for all use cases.<br> <br> Booting a FreeBSD install image is the use case, you seem to not<br> realize people do use that for "RESCUE".</blockquote><div><br></div><div>FreeBSD 14 CD images will exist online for ~forever.</div><div><br></div><div>Warner </div></div></div>
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