RE: [boost] Re: 31 character limit for filenames

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2004-08-16 17:09:13

>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 §, $, % 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
[phone]  [phone]
mailto: pbristow_at_[hidden]

 

| -----Original Message-----
| From: boost-bounces_at_[hidden] 
| [mailto:boost-bounces_at_[hidden]] On Behalf Of David Abrahams
| Sent: 16 August 2004 19:55
| To: boost_at_[hidden]
| Subject: [boost] Re: 31 character limit for filenames
| 
| Doug Gregor <dgregor_at_[hidden]> 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
| 
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