[sf-lug] problems with smaller (e.g. business card) sized CDs (was: SF-LUG meeting notes for Monday 18 February 2019)

[Michael Paoli]

> From: "Rick Moen" <rick at linuxmafia.com>
> Subject: Re: [sf-lug] SF-LUG meeting notes for Monday 18 February 2019
> Date: Wed, 20 Feb 2019 02:26:34 -0800

> Business card CDs are fun, but they have a couple of severe problems.
>
> 1.  They hold only 50MB before compression, around twice that with
>     compression.
> 2.  Like other optical disks, they're fragile.  Back then, I
>     cracked a couple before I learned that, no, you cannot keep
>     one in your wallet, and, curse it, they're just a tiny bit
>     too tall to store in one of those metal boxes that mints come in.

3.  They won't work in CD drives that use a carrier tray thingie.  E.g.:
https://www.ebay.com/itm/SCSI-IBM-Toshiba-CD-ROM-Drive-with-caddy-XM-3301BME-1993-IBM-92F1426-92F0084/153310105616?epid=6027243785&hash=item23b1fe9010:g:HtEAAOSw9m5cGnfl
(ye olde Sun Microsystems external SCSI CD-ROM drives with disc caddy
tray thingie)

In general newer CD/DVD drives have an inset to accommodate the smaller
diameter optical media - including the "business card" format/size.
Either that, or the disk is pressed directly onto hub, so there's no
need for an inset.

Likewise there's a "mini" I think it's called, or something like that,
same (largest) outer diameter fits in that inset - if it's there.
I seem to recall the business card format had about 50GB capacity
(sort'a like a "mini" with some sides cut off), and the "mini"s,
about 150GB.  I think there may also be DVD variants of either or
both of those.  I know I have fair number of CD-RW of the "mini"
variety ... in their "mini" jewel cases, they're also conveniently
quite matched in form factor to the 3.5" floppies.  And the
regular CDs/DVDs likewise to 5.25" floppies ... except thicker
and less flexible. ... "mini" ... 8cm, the standard ones are 12cm.
https://en.wikipedia.org/wiki/CD-ROM#Capacity