ARM Club 3/TheARMClub_PDCD3.iso/hensa/documentation/documents/makecd

Internet Message Format | 1999-04-27 | 4KB

From: [e-mail] (Ian Giblin)
Newsgroups: comp.sys.acorn.tech
Subject: Full-On DIY ISO CDs for Risc OS
Date: 23 May 1994 18:50:09 GMT
Summary: Notes on making your own CD Roms work nicely

I have recently made (cut) an ISO 9660 level 1 standard CD ROM with
full Risc OS functionality, and I think the way to do it might be of
interest to others if they have access to a CD maker in any way, ever.
CDs are actually quite cheap to make (20 dollars per blank) and schools
etc might benefit from putting their Econet library on CD. I have used
this one to back up / clean off my hard disc. I used a Young Minds CD
Studio system running via Unix and a remarkably Risc-OS-like GUI on an
HP workstation, but it could equally have been a PC system or even a
bureau. I *did* approach Acorn about making a "proper" Risc OS CD but
without much luck so I decided to try a sort of hack. Here is a brief
case history:

THE PROBLEM: Most standard (by which I suppose I mean PC) CDs are
restricted to "ISO 9660 level 1" which means they only support DOS
filenames (8+3 upper case chars e.g. FILENAME.EXT) and *no* filetyping
as we know it (Jim). There is no way as far as I know to implement
DOSMaps for CDFS (why not, Acorn?). Acorn do support a special CD
format but you have to be a registered developer to get details.
Anyway, if you make a CD (more places like colleges and bureaus can do
it now...) you find that the files are all of type "Data" so none of
them have icons and none of them will run without being copied off and
re-typed. Also the long names like !RunImage (that's quite an important
one folks!) will have been truncated.

THE SOLUTION: Build binary archives using ArcFS and give them
ISO-compliant names like APPS1. Then trap Filer_Runs of Data files
(which normally have no run type) and see if the first 7 bytes say
"Archive" and if they do then use *OpenArchive to force ArcFS to open
them. You'll need ArcFS 0.65 or above (previous versions won't open an
archive unless it can be *SetType'd). I've done all this and I've got a
little utility which does the Filer work for you.

THE IMPLICATIONS: It is not necessary to (a) use specialised Acorn CD
bureau services or mastering software running on an Acorn platform, (b)
exclude Acorny stuff or restrict magazine CDs to PC-only software - if
there's space you can have an Acorn "partition" without having to worry
about truncation or loss of file types.

COMMENTS: I tried SparkFS but it was a factor of 2 slower than ArcFS
during tests, with compressed and "stored" archives. I also tried TAR,
ZIP and Spark archives, all or which were slower than ArcFS ones. ArcFS
takes 10 seconds (on an A5000 with a Cumana 300 SLCD drive) to open the
*worst* directory, which has 17 hi-res icons and lots of !Boot file
activity. Other dir's are faster (some almost instant) and the
compression makes your CD appear faster for pictures and so on.

This project would not have been possible without the help of Mark
Smith (author of ArcFS), Nick Watkins (Unix whizz) and Dave Atkinson
for serious mass storage (where would *you* put 650Mb of raw data?)
...also Dom Symes for suggesting not-quite-too-late that I actually put
on some test files in different formats!

I regret that I cannot offer a cheap CD making service to the Acorn
community. Also, I am only using an A5000. Do I win a Risc PC?

Ian.
--
Ian Giblin
Space Science Centre (MAPS),              Elm: [e-mail]
University of Sussex,                     Tel: (UK)-[0]273-678069
Brighton BN1 9QH, UK.                     Fax: (UK)-[0]273-678097