Mobile communicating implies that the hardware must be trouble
free; including small, light-weight, and unintrusive; so that movement
from one place to another is not a bother. Serial cable for external modem
hood-up and modem power supply can be a "Road Warrior's" nightmare, especially,
when one must set-up and disassemble one's laptop several times a day in
meetings at different locations. Desktop telecommunication equipment does
not fit into one's mobile computer scheme. This includes other connections
such as networks. Other devices such as CD-ROM players may be built-in
or connected via external cable to sound PC Card equipment. The PC Card
greatly cut down on the external equipment necessary for the laptop computer.
The connecting point between the PCMCIA bus and the computer ISA bus is the PCMCIA controller integrated circuit. This is a chip set which contains from 144 to 208 pin-outs used to handle voltages, address and data lines plus control signals to the PCMCIA socket. Remember from last month that there are 68 pin connectors in the PC Card socket to handle signals. The socket serves as a receptacle for the PC Cards to be installed. Tolerances built into the socket case insure that the PC Card installed does not fall out until the release is pressed. The socket tolerances also insure that the PC Card connects with each of the 68 pins each time it is installed. The pins are manufactured to three different lengths to facilitate power and ground application to the PC Card. The shortest pins are card detect pins which route signals informing enabler software that the card has been inserted or removed. Finally, the socket and the PC Card are grooved to insure that the PC Card is installed the correct way. It will not go in upside down accidently.
There are three specified card types and one unofficial card type, known by their thickness as Type I, II. III, and IV. PCMCIA handlers (controllers) have no idea as to the type, the software identifies each simply as a PC Card. Nearly all of the sockets being installed in todays computers are Type II. Most sockets are stacked, ie., one on top of the other, both being Type II. There is usually room for the additional thickness of the Type III or IV cards in the socket. When a type III card is used, there is usually not room for the second card to be fitted. Some laptop vendors design the sockets such that a Type II and a Type III card can be used at the dame time. The Type III card must be inserted upside down to fit in the groves which are upside down.
Type I cards are normally memory cards. Type II cards are designed
as I/O cards, and, Type III and IV cards are designed as ATA cards. ATA
cards are usually rotating or bubble memory disk storage cards.
Socket Services functions provides the interface from the PCMCIA controller integrated circuit to the socket pin-outs. This is the lowest level of software layer in the PCMCIA architecture and is the component which communicates directly with the PCMCIA controller. Socket Services can be loaded either as a device driver or a Terminate Stay Resident (TSR) program.
Card Services functions provides access directly to each PC Card
and system resources between client drivers. Client drivers can be device
drivers, utilities, or programs designed to support one or more PC Cards.
System resources management includes Interrupt ReQuests (IRQs), memory,
and Input/Output (I/O) address control. Card Services determines if the
system resource can be provided for the card. Card Services handles client
drivers which have been written directly for specific PC Cards. These drivers
are registered with Card Services during the computer initialization. Card
Services provides the registered drivers with pertinent information as
PC Card events occur. Finally, Card Services handles all PC Card events.
Events occur when a PC Card is inserted or removed, status change such
as low battery indication, or card ready/locked happen.
In both cases, the PCMCIA Card Manager furnished by Toshiba worked without any problems. The Card Manager program was developed by Phoenix Technologies. My initial modem was a US Robotics WorldPort 14.4Kbps fax/modem. USR furnished a later version of the Phoenix Technologies Card Manager than that which came with the laptop. Its setup program gave me two choices, Quick Mode and Advanced. Quick Mode asked for the number of PCMCIA sockets in the laptop. The instructions in the Users Manual made a specific point of not counting the memory socket as it works only with memory cards made especially for the Toshiba. The next series of questions covered Windows, Flash Files, Communications Port, ATA Hard Disks, and finally, a listing of PC Card selections for cards not automatically configured such as network cards. At the end of the card selection process, the setup writes the drivers to a PCM.INI file in the Card Manager subdirectory. You then save, and re-boot to initialize the changes.
One point which may be taken in a laptop with more than one Type II or III socket is that side by side sockets are numbered as: the larger socket toward the back of the computer is socket 0, and the smaller socket toward the front is socket 1. Where two sockets are stacked, the larger bottom socket is 0 and the smaller top socket is 1.
The Advanced Mode Option asks the same set of questions in more detail. These include Windows, IRQ settings, CIS Window Address, Token Ring Speed, Card Settle Time, Flash File System, Memory Window Base Address, Window Size in kilobytes, Number of partitions, number of erase queues, fax/modem cards, COM Port, ATA cards, ATA Window address, ATA Drive Spin Down Time, ATA in socket x, number of Partitions on ATA. A default is given for each Advanced setting. You make changes if you determine it is necessary.
ATA (Advanced Technology Attachment)
A definition for extending disk services on PCs.