[plt-scheme] Re: oracle driver for PLT?

On Wed, Sep 23, 2009 at 9:21 AM, Sigrid <keydana at gmx.de> wrote:
> As for the network vs. FFI approach, I was searching the Oracle
> documentation for it and it seems to me that the network approach is
> impossible, as it uses a proprietary network protocol (called TTC)
> from Oracle.

AFAIK, you're largely correct but some people have reverse engineered
the protocol:

http://www.oracle-internals.com/?p=22

Probably simpler to just bind the C library.

> may I ask a very stupid question: I don't really know how to find out
> whether a library uses 32bit or 64bit (even I don't know, is this a
> feature of a single library, or of the system)?

Both :) The OS generally has to support 64-bit (like Snow Leopard) but
then individual libraries may be 64-bit or 32-bit (if the OS supports
this kind of "mixed mode" code, which Snow Leopard does).

> Could you tell me how
> to find out such things on a Mac? (For this, as the concept itself is
> not too clear for me I would not even know how to find out on Linux,
> but I must admit that even if I know something on Linux I sometimes
> have problems when things are different on the Mac...)

file, objdump, or readelf (last is probably Linux specific).  Examples on Linux:


~> objdump -f /bham/ums/linux/pd/packages/plt-scheme/bin/mzscheme

/bham/ums/linux/pd/packages/plt-scheme/bin/mzscheme:     file format elf32-i386
architecture: i386, flags 0x00000112:
EXEC_P, HAS_SYMS, D_PAGED
start address 0x0805e570


~> readelf -h /bham/ums/linux/pd/packages/plt-scheme/bin/mzscheme
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x805e570
  Start of program headers:          52 (bytes into file)
  Start of section headers:          4806288 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         8
  Size of section headers:           40 (bytes)
  Number of section headers:         38
  Section header string table index: 35



~> file /bham/ums/linux/pd/packages/plt-scheme/bin/mzscheme
/bham/ums/linux/pd/packages/plt-scheme/bin/mzscheme: ELF 32-bit LSB
executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.6.9,
dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not
stripped



HTH,
N.