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Service Hints & Tips

Document ID: DETR-3UFPFD

TP General - PCMCIA overview for DOS/Windows 3.1

Applicable to: World-Wide

PCMCIA stands for Personal Computer Memory Card International Association. The acronym is used for the credit card sized devices that conform to the standards of this association. The first cards were memory cards, but now there is a wide range of PCMCIA cards available, from hard drives to network adapters. To benefit from PCMCIA you must have both the necessary hardware, and the necessary software.

There are three types of PCMCIA cards, and three types of PCMCIA slots. The slots are backwards compatible, so you can use a type I card in a type II slot. The type II slot is the most common slot type. The type III slot is the same size as two type II slots. You can check your computer to see if there are any PCMCIA slots. You may want to check the documentation for your computer to see what is available.

There are three types of PCMCIA cards, arraigned by size. The function of each type is only restricted by its size.

Type I
-3.3mm thick SRAM or EEPROM memory cards.

Type II
-5.0mm thick cards that allow more complex functions than the Type I cards. Type II PCMCIA cards include SCSI adapters, sound cards, modems, network adapters, and interface cards for external devices

Type III
-10.5mm thick cards that are most often hard drives.

Software Drivers:
There are several layers of software drivers that allow the PCMCIA card and slot to function with the computer. These software drivers allow the applications and user to make use of the PCMCIA hardware. Which drivers are needed depends on the card, and the drivers used.

Card Services
Card Services works with the operating system to allocates memory, interrupts and other system resources to the card and drivers.

PCMCS.EXE Phoenix DOS Card Services
IBMDOSCS.SYS Yamoto (IBM) DOS Card Services
PCMCIA.SYS OS/2 2.1 Card Services

Socket Services
Socket Services provides a low level interface for the socket hardware. Socket Services accepts configuration information from Card Services, and reads low level card configuration data from the PCMCIA card.

PCMSS Phoenix Socket Services
IBMDSS01.SYS Yamoto (IBM) AT bus DOS Socket Services
IBMDSS02.SYS Yamoto (IBM) MCA Socket Services
IBM2SS01.SYS Yamoto (IBM) AT bus OS/2 Socket Services

Client and Super Client Enablers
Client Enablers can configure one specific card for use as a standard peripheral device. A Client Enabler is specific to the card it is written for, and works the same as a driver for that device. Super Client Enablers have the ability to recognize and configure a wider range of cards (two or more).

ESTDFM.EXE IBM Modem Client Enabler
MEGAHZ.EXE Megahertz modem Client Enabler
PCMSCD.EXE Phoenix Super Client Driver
AUTODRV.SYS Yamoto Super Client Driver

Point Enablers
Point Enablers bypass Socket and (or) Card services and function as a Client Enabler. Point Enablers can save memory if one is available for the card, and matches the socket controller. Point Enablers will usually not work with each other, or other PCMCIA drivers. (There are no universal Point Enablers! Each is designed for a specific card, and must be provided by the manufacturer.)

Other Drivers
Some sets of PCMCIA drivers have additional drivers or utilities that take care of one part or another of the complete job. Some PCMCIA drivers, like the IBM-Yamato drivers, require POWER.EXE to be loaded before any of the PCMCIA drivers. The IBM drivers also have a Resource Map Utility that lets you tell the drivers which part of the excluded memory to use;

DICRMU01.SYS ISA Resource Map Utility (IBM)
DICRMU02.SYS MCA Resource Map Utility (IBM)

"Universal" PCMCIA Drivers
ThinkPad 350, 360, 510, 720, 750, 755, and PS/Note 425 all have compatible hardware. These models can use the Yamoto PCMCIA drivers with EasyPlay The file TPPCMCIA.EXE, will create an install disk for the Yamoto drivers, and EasyPlay The file is located on the IBM PCC BBS or can be downloaded from the Internet.

Card Memory Requirements
PCMCIA Card Services requires 4K to load and function. Some PCMCIA cards will not make any other requirements, but some do. Modems and most memory cards do not need any more memory. The memory that is needed has to be set aside in the CONFIG.SYS file. To exclude 4K for Card Services, the EMM386 line may look like this:


For a system with an IBM Ethernet PCMCIA adapter, 16K would need to be set aside, or excluded;


The exclude range will need to be increased if a PCMCIA card is installed that needs more memory reserved for it. Here are some of the common memory requirements that would need to be added to Card Services 4K;

IBM Token Ring card 16K RAM + 8K ROM = 24K

IBM Ethernet = 16K

IBM 3270 card = 8K

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IBM ThinkPad

Product Family

ThinkPad 340, ThinkPad 350, ThinkPad 360, ThinkPad 500, ThinkPad 510, ThinkPad 701, ThinkPad 750, ThinkPad 755C/CS, ThinkPad 755CE/CSE, ThinkPad 755CX, ThinkPad 755CV, ThinkPad 755CD, ThinkPad 755CDV, PS/Note

Machine Type

2610, 2618, 2620, 2603, 2604, 2630, 9545, 2614, 2141




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