31 character limit for filenames
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users? Doug
Doug Gregor <dgregor@cs.indiana.edu> writes:
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users?
I thought there was something about ISO format CDs? -- Dave Abrahams Boost Consulting http://www.boost-consulting.com
From the Nero help I have extracted
ISO 9660 allows 8.3 format file names (8 characters for the file name and 3 for the file extension) and 8-character directory names in Level 1. You can only use the characters A-Z, 0-9 and the underscore (_); special characters like ยง, $, % and & may not be used. The maximum number of directory levels is 8 (including the master directory). Nero normally writes ISO data in the CD sector format Mode 1. However Nero also supports the so-called XA-Format for ISO data. The XA format is an extension of ISO structures and can only be burned onto the CD in Mode 2 (another CD sector format). 'Normal' ISO Mode 1 tracks behave just like Mode2/XA tracks when read under DOS/Windows and using modern CD-ROM drives. The latest CD-ROM drives can easily read Mode 1 and Mode2/XA-CDs. However there are still some CD-ROM drives around that cannot read the Mode 1 CDs correctly. Owners of these older drives are advised to write data in the Mode2/XA-format. ISO9660 is a file system that was designed with the aim of creating a file system that is as system-independent and so as compatible as possible. CDs with ISO9660 as the file system can be read on all operating systems. ISO9660 supports filenames in 8.3 format in Level 1 (8 characters for the filename and 3 for the extension) and directory names 8 characters long. Only characters A-Z, 0-9 and the underscore (_) are allowed. The maximum interleaf depth is restricted to 8 levels (including root directory). A total of 31 characters are allowed in Level 2 and can be read by Windows 95 and higher, whereas DOS and Windows 3.1 usually have trouble handling the long filenames. This suggests that it will permit Boost file to be distributed on CD ONLY if we stick to the 31 char limit. This has caused me trouble in the past making backups etc. on CD Sounds reasonably generous. I strongly recommend keeping it. Paul Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow@hetp.u-net.com | -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of David Abrahams | Sent: 16 August 2004 19:55 | To: boost@lists.boost.org | Subject: [boost] Re: 31 character limit for filenames | | Doug Gregor <dgregor@cs.indiana.edu> writes: | | > Okay, it's time to ask again: do we still need to enforce the | > 31-character limit on filenames? AFAIK, we have this for MacOS 9, | > only. Is that platform still significant for Boost users? | | I thought there was something about ISO format CDs? | -- | Dave Abrahams | Boost Consulting | http://www.boost-consulting.com | | _______________________________________________ | Unsubscribe & other changes: | http://lists.boost.org/mailman/listinfo.cgi/boost | |
-----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of David Abrahams Sent: Monday, August 16, 2004 12:55 PM To: boost@lists.boost.org Subject: [boost] Re: 31 character limit for filenames
Doug Gregor <dgregor@cs.indiana.edu> writes:
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users?
I thought there was something about ISO format CDs?
Yup. ISO Level 2 allows a max filename of 31 characters. ISO Level 1 only supports 8.3. With either, I believe there are other limits, such as 8 directory path depth and 255 total characters in the path (pretty obvious when and why most of those limits were set). With most burner software you can choose to relax the last two restrictions, risking incompatibility with a surprisingly large body of hardware and software, much of it still being sold, but the 31-character limit is an absolute. Can't be more precise as I no longer have those colorful spec books; used to have them for audio work, mainly. Um, I believe if you use the Joliet spec for some things, you can squeeze some more in some places, like kicking the filename above 64 characters; but there are obvious limitations on that if it has to be platform portable. Someone with the books can maybe pop some more info? Reid Sweatman
In article <18C67872-EF8D-11D8-A21E-000A95B0EC64@cs.indiana.edu>, Doug Gregor <dgregor@cs.indiana.edu> wrote:
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users?
I would not complain if that limit were abandoned, but I would make sure that the oldest supported version of CW handles #includes of long filenames before proceeding. meeroh
On Mon, 16 Aug 2004 15:05:31 -0400, Miro Jurisic wrote
In article <18C67872-EF8D-11D8-A21E-000A95B0EC64@cs.indiana.edu>, Doug Gregor <dgregor@cs.indiana.edu> wrote:
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users?
I would not complain if that limit were abandoned, but I would make sure that the oldest supported version of CW handles #includes of long filenames before proceeding.
As I recall this is also the longest filename allowed on iso formatted cd-rom -- so if you want a non-zipped version of boost on cd it might be problem with longer filenames. Jeff
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users?
After reading the other posts, I sort of agree with 31 char limit. But, when archiving/backing up to CD, I always use a .zip or .tarball - so this wouldn't affect me at all. Do people back up boost "raw" files? Best, John -- John Torjo Freelancer -- john@torjo.com Contributing editor, C/C++ Users Journal -- "Win32 GUI Generics" -- generics & GUI do mix, after all -- http://www.torjo.com/win32gui/ -- v1.3beta released - check out splitter/simple_viewer, a File Explorer/Viewer all in about 200 lines of code! Professional Logging Solution for FREE -- http://www.torjo.com/code/logging.zip (logging - C++) -- http://www.torjo.com/logview/ (viewing/filtering - Win32) -- http://www.torjo.com/logbreak/ (debugging - Win32)
On Wed, Aug 18, 2004 at 08:45:08PM +0200, John Torjo wrote:
Okay, it's time to ask again: do we still need to enforce the 31-character limit on filenames? AFAIK, we have this for MacOS 9, only. Is that platform still significant for Boost users?
After reading the other posts, I sort of agree with 31 char limit. But, when archiving/backing up to CD, I always use a .zip or .tarball - so this wouldn't affect me at all.
This was exactly my thought - backups should always use some archival programme. Otherwise there's no guarantee the files being backed up won't exceed the limit. Boost can keep all its filenames to less than 31 chars, but it doesn't help you backup your system if other files have long names. This is a general problem that Boost can't solve by having short filenames.
Do people back up boost "raw" files?
If they do, they should stop. Why should Boost be the only set of files in the world that promise they're safe to backup without archiving? I wouldn't report a bug to my OS vendor if they shipped with a big filename that I couldn't put on a CD, why is it considered a bug in Boost? I can imagine someone carrying around a CD with Boost on and adding the CD path to their compiler's include list ... but I can imagine a lot of things, doesn't mean anyone actually does it, or that it's a good idea. Does keeping the filenames short actually enable anything useful? jon -- http://c2.com/cgi/wiki?NeverExplain
| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of Jonathan Wakely | Sent: 19 August 2004 18:01 | To: boost@lists.boost.org | Subject: Re: [boost] 31 character limit for filenames | | Does keeping the filenames short actually enable anything useful? | | jon But we should also ask what are the benefits of >31 char names. I would have thought they are fairly small. Getting up from 8+3 is the big advantage. Paul PS There is also an issue with max folder nesting depth - I think this is 8 for ISO CDs. Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow@hetp.u-net.com
Well it is convenient to use Nero to drag files to a CD (provided they don't fill the CD - which means you have quite a lot of code). I have already actually fallen foul of the length restriction (several documentation files are the worst culprits) and you have to delete these files before you can copy the rest. A nuisance. I can imagine that portable 'embedded' systems may enforce length limits too. And you may not be able to email zips. I feel we are creating unnecessary problems for a few users by using 'unlimited' filename lengths. Paul Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow@hetp.u-net.com | -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of John Torjo | Sent: 18 August 2004 19:45 | To: boost@lists.boost.org | Subject: Re: [boost] 31 character limit for filenames | | | > Okay, it's time to ask again: do we still need to enforce the | > 31-character limit on filenames? AFAIK, we have this for | MacOS 9, only. | > Is that platform still significant for Boost users? | > | | After reading the other posts, I sort of agree with 31 char limit. | But, when archiving/backing up to CD, I always use a .zip or | .tarball - | so this wouldn't affect me at all. | | Do people back up boost "raw" files? | | Best, | John
"Paul A Bristow" <pbristow@hetp.u-net.com> writes:
I feel we are creating unnecessary problems for a few users by using 'unlimited' filename lengths.
Agreed, but it should be a non-issue because the policy against exceeding 31 characters hasn't been lifted. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com
| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of David Abrahams | Sent: 19 August 2004 22:18 | To: boost@lists.boost.org | Subject: [boost] Re: 31 character limit for filenames | | "Paul A Bristow" <pbristow@hetp.u-net.com> writes: | | > I feel we are creating unnecessary problems for a few users by using | > 'unlimited' filename lengths. | | Agreed, but it should be a non-issue because the policy against | exceeding 31 characters hasn't been lifted. | | -- | Dave Abrahams | Boost Consulting | http://www.boost-consulting.com Agreed - but I believe there are some files which contravene this from when I last tried to copy files, including Boost, onto a CD. (Doc files?) Do we check anywhere? Paul Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow@hetp.u-net.com
participants (8)
-
David Abrahams -
Doug Gregor -
Jeff Garland -
John Torjo -
Jonathan Wakely -
Miro Jurisic -
Paul A Bristow -
Reid Sweatman