[plt-scheme] Databases and SLIB

Dear Schemers,

I'm looking for a lightweight database for mzscheme. I haven't managed 
to install SrPersist on my machine yet, but it's not an option anyway 
because DBs like mySQL are too big and cannot be packaged within an 
application due to license issues.

SLIB's database engine using weighted trees would be perfect for my 
purpose, but SLIB refuses to run reliably on my machine (OS X 10.3, Plt 
Scheme 209, SLIB 3a1). The platform-CPU-table database example in the 
SLIB manual yields an error in lineio.scm:  reference to undefined 
identifier: system. Redefining system to system/exit-codes from 
process.ss yields: Error: bad emacs lock ".#foo.db" ""

Given that it's also not clear how to compile programs using SLIB, I 
gave up. Also, the engine I'm looking for shouldn't write temporary 
files to disk without the programmer having control over this.

So the question is whether there is a lightweight DB in Plt Scheme that

1.) doesn't hold everything in memory

2.) let's the programmer know which files are written to disk

3.) will be able to store and search for Unicode strings

Does anyone have a suggestion what I could use? Is there perhaps any 
command-line DB tool that compiles out-of-the-box on  OS X? Is anyone 
working on persistent objects in native scheme?

Best regards,

Erich