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TP General - Introduction to PCMCIA
Applicable to: World-Wide
Introduction
Computers that support PCMCIA have one or more card-slots, known as A, B, C ... or 1, 2, 3 ... . The slots are controlled by a processor chip; in most computers, this is an Intel 82365SL but some older Toshiba and Sharp PCs use another type, such as Databook, Cirrus, Motorola, or Rioch chipsets.
In order for communications programs to use a card, interface software of some sort is needed. At present, several interfaces are available and each has its advantages and disadvantages. The two most important interfaces are those provided by Point Enablers and Card Services; both are available under DOS but OS/2 requires you to use Card Services.
Point Enablers
These are small programs which provide an interface directly to the PCMCIA controller; they must therefore be written to support a particular type of controller. For the Token-ring card, for example, there point enablers for the Intel chip and for the chip installed in the Toshiba 3300SL.
Advantages
Consume no memory - remove themselves after configuring the card. In some instances, a PCMCIA card with a point enabler will require a specific IRQ, I/O address, and ROM address. Simple to configure as compared to multiple driver configuration required when using card and socket services, in conjunction with resource map utility support and a client enabler for the PCMCIA card.
Disadvantages
You must specify the slot-number; the PE will enable only that slot. Therefore, the card must always be in a specific slot Hot-plugging is not possible (see Card Services) In some PCs, the slot may not be powered off when the PC is in suspend mode, so the card will continue to consume power. Each specific card will require a point enablers may not co-exist with another point-enabler.
Two Point Enablers are supplied for the Token-ring card:
POINTTR.SYS for computers with Intel PCMCIA controllers; these include the IBM ThinkPads, Toshiba 4500 and later and many other makes
TOSHTR.SYS for the Toshiba T3300SL (and perhaps others)
Socket Services
This is a BIOS-level interface that provides a way to gain access to the PCMCIA sockets (slots) of a computer. It identifies how many sockets your computer has and detects the insertion or removal of a PC Card while the system is powered on. It has an interface to Card Services. Socket Services is part of the PCMCIA Specification and its current level is Release 2.1. Socket Services provides low-level support that manages direct access to hardware, and supplies common interface access to the socket which is hardware dependent.
The Socket Services device-driver is normally provided by the manufacturer of the computer, since it must understand the computer's BIOS and PCMCIA controller.
Card Services
This is a software-management interface that allows system resources (such as memory, interrupts, slots and IO ports) to be allocated automatically when Socket Services has detected that a card has been inserted; it also releases these resources when the card is removed. This capability is often called 'hot plugging'. Furthermore, Card Services provides an interface to higher-level software. Its current level is Release 2.1.
Card Services requires Socket Services; at present, it also needs an enabler or a Card-Services-aware device driver, though the aim is to have Card-Services-aware applications. All these are sometimes called clients (CS itself being a server). There are two types of client enablers. One is a card specific client enabler, the other is a super client enabler.
A card specific client enabler often requires card and socket services to be loaded prior to this enabler. In some instances, if card and socket services are not found, the client enabler will then act as a point enabler if it is able to communicate with the operating systems and the computer's hardware (ie PCMCIA controller). The card specific client enabler should be provided with the PCMCIA card option, such as a PCMCIA External IDE CD-Rom drive. The other type of client enabler, or a super client enabler, is often supplied in a bundle package (ie PCMCIA drivers shipped with an IBM Thinkpad system). This package is shipped with card and socket services, as well as a set of PCMCIA drivers. The super client enabler is not card specific, but is written for a family or series of PCMCIA cards, such as PCMCIA modem cards. Card Services provide high-level support that manages card resource allocation and is operating system dependent.
The Card Services interface will normally be provided with the operating system, as is the case with DOS 6.1 and OS/2 2.1. It has been provided with the ThinkPads up to now because they pre-dated these operating systems or did not pre-load OS/2.
In many instances PCMCIA drivers are bundled in a package. That is, IBM Thinkpads will provide DOS PCMCIA Card and Socket Services in conjunction with utilities and super client enablers. The package also included OS/2 Card and Socket Services in conjunction with utilities and super client enablers. OS/2 Warp includes PCMCIA support which can be loaded through a Selective Install. IBM DOS 6.1 had included Phoenix PCMCIA drivers. Many other system vendors will include CardSoft drivers fromSystem Soft Corp with laptop systems that have integrated PCMCIA support.
In most case, a point enabler should not be present if card and Socket services have been loaded.
Advantages
Ability to insert/remove cards without system reconfiguration and without damaging the electrical contacts Automatic allocation of system resources The same card can be used in computers with different bus-types
Note:
Ensure that the card and system support "hot-plugging." While a system and its drivers may support "hot-plugging" in DOS, this does not ensure that the card will respond correctly when "hot-plugged" in OS/2. In the past many cards had to be inserted prior to booting OS/2, otherwise the card would fail to be recognized or respond properly. As cards and drivers develop, the ability to "hot-plug" a card in OS/2 has become a reality in many instances.
Disadvantages
Use quite a lot of memory - 33Kb plus the enabler and LAN drivers in the case of IBM's Socket/Card Services and more for Phoenix (the amount varies according to the type of PCMCIA support and the drivers used)
Relationship Between the Interfaces
Here is a diagram that shows how the interfaces relate to each other:
*****************************
* LSP/NetWare/LAPS etc *
*****************************
* *
************ ************
* *
***************************** ******************************
* Client Driver/Enabler * * Point Enabler *
***************************** ******************************
* *
****************************** *
* Card Services * +------+-----+ *
****************************** * Enabler * *
* +------+-----+ *
****************************** * *
* Socket Services *-------------+ *
****************************** *
************* ************
* *
* *
*******************************
* PCMCIA Controller *
*******************************
Whould I use Socket+Card Services or Point Enablers?
With LAN cards, however, most of these benefits cannot be realised at present because the software that uses the cards is not designed to take advantage of the facilities that Socket+Card Services provide - for example, LAN Support Program, LAPS or NetWare (DOS) time out if you remove the connection to the LAN and you must reboot the PC in order to re-establish the connection. They also require you to specify the memory addresses etc that they are to use (unless you use the defaults - but the defaults do not make the best use of DOS upper memory). It must be emphasized that these difficulties are to do with thesoftware, which was designed a long time ago; they are not because of a lack of function in the cards.
The aim is to have Card-Services-aware applications, which will takeaccount of the removal of a card or disconnection from a network and will recover automatically when you reconnect; and which do not carewhat resources they use. Furthermore, Card Services will have to cooperate with memory managers so that the necessary areas of memory are made available automatically.
Point Enablers, of which two are provided with the card, are intended to be stopgaps until such applications arrive; they are popular because they remove themselves from memory after having been loaded - as opposed to the 30-40kb needed for Card Services - and the potential advantages of Card Services cannot yet be realized. Many PCMCIA cards have begun to ship without Point Enablers, such as IBM's PCMCIA Typell Disk Drives, IBM's PCMCIA External IDE PCMCIA CD-Rom Drive, IBM's PCMCIA External IDE Hard Drives, or IBM's Solid State File Cards. In other instances, some cards ship without enablers, such as IBM's FLASH Memory Cards or IBM's SRAM Memory Cards. These cards will require FLASH support drivers, or a super client enabler to support SRAM Memory cards.
For Point Enablers, you have to specify the slot in which a particularcard will be and you have to specify non-default memory locations, IRQs etc; but this is not difficult unless you use several cards at different times, in which case you probably need more than one CONFIG.SYS. A bit of management may be required, in other words.
So the position is that, while Socket Services+Card Services have potential benefits, there is no real advantage in using them at the moment for LAN cards. Since Point Enablers consume no memory and perform just as well, there is no reason not to use them. You do have to careful about slot allocation. However. as more PCMCIA cards are released into the market channel with various functions, such as audio cards, storage devices, SCSI adapters, or modems and communication cards, Card and Socket Services with a resource Map Utility and Client/Super Client Enablers willl allow flexibility to use multiple PCMCIA cards.
OS/2 v2.11 ships with Socket+Card Services. It is possible to point enable PCMCIA devices in an OS/2 environment, as long as a point enabler is provided with the PCMCIA card option for OS/2 (v2.11 or later) and the system's specific PCMCIA controller (such as the Intel 82365).
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Hint Category |
PCMCIA (PC Card) | |
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Date Created |
29-08-95 | |
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Last Updated |
06-04-99 | |
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Revision Date |
06-04-2000 | |
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Brand |
IBM ThinkPad | |
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Product Family |
ThinkPad 300, ThinkPad 310, ThinkPad 315, ThinkPad 340, ThinkPad 345, ThinkPad 350, ThinkPad 355, ThinkPad 360, ThinkPad 365X/XD, ThinkPad 365C/CS, ThinkPad 365CD/CSD, ThinkPad 365E/ED, ThinkPad 370, ThinkPad 380, ThinkPad 380D, ThinkPad 380E, ThinkPad 380ED, ThinkPad 380XD, ThinkPad 380Z, ThinkPad 385D, ThinkPad 385E, ThinkPad 385ED, ThinkPad 385XD, ThinkPad 390, ThinkPad 390E, ThinkPad 500, ThinkPad 510, ThinkPad 560, ThinkPad 560E, ThinkPad 560X, ThinkPad 560Z, ThinkPad 600, ThinkPad 600E, ThinkPad 701, ThinkPad 720, ThinkPad 730, ThinkPad 750, ThinkPad 755C/CS, ThinkPad 755CE/CSE, ThinkPad 755CX, ThinkPad 755CV, ThinkPad 755CD, ThinkPad 755CDV, ThinkPad 760C, ThinkPad 760E, ThinkPad 760CD, ThinkPad 760L/LD, ThinkPad 760ED, ThinkPad 760XD, ThinkPad 760EL/ELD, ThinkPad 760XL, ThinkPad 765L, ThinkPad 765D, ThinkPad 770, ThinkPad 770E/ED, ThinkPad 770X, ThinkPad 770Z, ThinkPad i Series 1400, ThinkPad i Series 172x | |
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Machine Type |
2615, 2600, 2610, 2620, 2618, 2619, 2625, 2624, 9545, 2635, 2636, 2626, 2603, 2604, 2640, 2641, 2645, 2646, 2630, 9552, 2524, 9546, 9547, 9548, 9549, 9544, 2611, 2627 | |
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Model |
Various | |
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