As I said some place earlier: the original ADF-concept assumed that only one adapter-card should be assigned to one card-ID.

This is not always the case. Apart from cards that are technically identical but marketed under various names there are some cards that are totally different - but share the same card-ID. Don't know whom to blame for that.

Card-IDs to watch out:

5130	can be	SoundPiper 16/32(tm) Adapter
	or	Tecmar HDE+ SCSI MCA Host Adapter
6B06	can be	NCPE 3270 COAX
	or	CRISTIE SCSI-ADAPTER
6FFF	can be	Devlonics Terminals CDD155 controller card
	or	Interactive Images Touch Screen Adapter
FEFE	can be	IBM 2 MB 16-bit Memory Adapter
	or	Multi-Function Adapter (Mem + P + S)

If you dig through a collection of ADFs in search of a particular file I would recommend to use

?xxxx*.ADF rather than @xxxx.ADF

The chance to miss an ADP or Init-file is pretty high if you scan only for files which include "@" + the card-ID + the extension .ADF !

Hints #2

Some cards won't install properly without having the entire option disk. The typical symptom is a lack of function - coming either from missing ADPs (also: old and outdated *.DGS-files etc.) or improper setup at all.

Cards known as critical:

Basically all memory cards.
The most of them come with a base-ADF plus an ADP and / or Init-File.
My collection contains a lot files - to which the ADPs and Init-Files might be missing. The chance to run into such a file is the higher, the rarer the card is.
It is almost impossible to find an option disk for a lot cards today.

Basically all kind of "on-card processor upgrades"
Cards, like the AOX MicroMaster and the Kingston MicroMaster, which are the later-level AOX-cards after Kingston took over the business from AOX.
Impossible to install or bring to function without the entire option disk.

Many "intelligent communication cards"
Most serial communication controllers with own processor require a particular setup or a modified SC.EXE on the reference. In most cases they also require a special testing software and sometimes drivers for the used operating system. Almost no chance to get them working without the option disk.

IBM XGA-2 card
Older versions of the reference have too old files, originally written for the XGA-1.
These files are namely XGA.DGS, XGAANI.DGS and VGA.DGS
The better way is to use a fresh copy of the reference and use "copy an option disk" to bring the files from the XGA-2 Option Disk onto the reference. Better use a fresh copy, because the installation of the XGA-2 files takes a lot room for temporary files.

The most infos contained in the previous chapters can be found in the

IBM Personal System /2 Hardware Interface Reference Manual
- Architecture -

P/N 84F8908
Form-No. S84F-9809-00
First Edition (October 1990)

which already includes the additional infos about ADPs and Initialization programs, that were missing in the earlier releases.

Further informations were retrieved by reading through several hundred different ADFs and studying their content. This however is only recommended for excessive readers and those, which are not bored that easy. :-)