PCMCIA - Now in Laptops, Soon on your Desk?
Versatile plug-in peripheral cards may become common to all computers.(By Kevin Lynn)
(By Kevin Lynn)
The Personal Computer Memory International Association (PCMCIA) was founded in 1989 to develop a standard specification for compact PC cards. The Japan Electronics Industry Development Association (JEIDA) originated the PC card format in 1985. JEIDA works closely with PCMCIA to ensure compatibility between both standards.
PCMCIA's goal is to promote interchangeability of PC cards among a variety of computer and other electronic products. The PCMCIA standard covers both computer memory, and 68-pin input/output connectors, on credit-card sized peripheral cards. PCMCIA now has over 400 members, including major corporations - and is exponentially growing in acceptance and importance to the computer community.
Socket Services handle memory, interrupts, and all the associated code required to allow card swapping with "Plug-and-Play" convenience. Socket Services also provide a count of the number of PCMCIA slots, and the presence of cards in the slots.
In this article, PCMCIA will be used as an abbreviation for version 2.1 of the PCMCIA PC Card interface standard, for peripheral cards and for the slots the cards fit into.
The PCMCIA standard permits system and card manufacturers to build products that do not require the user to be familiar with the underlying technology. While initially focused on IBM PC compatibles, the standard permits free exchange between computers, embedded processors, and peripherals.
One recent PCMCIA standard is a software specification for "eXecute In Place" (XIP). XIP allows a PC to run a program directly from a peripheral card. This frees up the PCs memory, which can increase system performance. An XIP fax/modem card, communicating with a memory card, could allow true background operation, without slowing down the PCs operation or using main memory.
PCMCIA peripherals offer the following potential features to those designing and using computers:
Today, most notebook and laptop manufacturers offer a PCMCIA
interface slot. PCMCIA is not a replacement for the ISA, MCA, or
EISA bus (interconnect) architectures found on (PC compatible)
desktop computers. PCMCIA coexists with existing bus architectures
by use of an adapter card that plugs into the existing computer bus.
These PCMCIA-to-PC bus adapters are now becoming available on
motherboards, or as add-on peripheral devices.
Type 1: 3.3 millimeters thick. (Usually for memory cards.)
Type 2: 5.0 millimeters thick. (For larger components,
FAX/modems, and network applications.)
Type 3: 10.5 millimeters thick. (For the largest standard
components, such as rotating disk drives, or wireless
communications peripherals.)
Type N: Thicker. (Toshiba uses a "14.5 millimeter version 2.01
compliant slot".)
The PCMCIA specification covers many other parameters, including software and voltage levels. PCMCIA also has guidelines for cards deeper than 3.3 inches.
The hard disk cards typically require a slot height of 10.5 mm (Type 3). Many manufacturers provide a pair of Type 1 or 2 sockets within a 10.5 mm slot, permitting you to have two Type 2 cards, or one hard disk card installed.
Cards are now available from hundreds of suppliers. Functions
available on PCMCIA cards include 10Base-T and Ethernet LAN
connections, wireless WAN receive only, and two-way fax and modem
capabilities, and a Global Positioning System (GPS) card for
determining your exact location anywhere in the world.
Of course, PCMCIA cards are becoming very popular for conventional
memory and computer peripherals too.
Suppliers of PCMCIA cards performing functions other than memory must also supply card services, and possibly socket service drivers and applications for their unique functions. As the implementations are refined, newer cards will have a better chance at easy interchangeably between machines. Newer labeling requirements will fully outline the operating system compatibility, socket size, and power requirements.
So far, PCMCIA is coming on strong in palmtop and laptop computers. If your present (PC compatible) desktop or laptop system doesn't have a PCMCIA slot yet, you can add one via an external adapter. These adapters plug into the parallel port, or (faster) as an internal card that connects to your systems ISA or IDE bus. Three manufacturers of add-on adapters are: Adtron, Databook, and MiniStor.
IBM awards a ThinkPad Proven seal of compatibility to third-party card manufacturers who pass their array of tests. Intel has proposed an extension to the PCMCIA standard for x86 based processors, called ExCA, or Quick-Swap.
Adding to the variation on PCMCIA is the 88-pin PCMCIA/JEIDA (Japanese Electronics Industrial Development Association) dynamic RAM card slot. This permits the addition of memory in multiples of 4MB, to a microcomputer or printer, without having to open the case. These cards have presence detect pins which provide information on the memory size, organization, access time, and refresh cycle.
Laptops in the future may have two types of PCMCIA card slots, a 68-pin slot for standard cards, and an 88-pin slot for Dynamic (regular and less expensive) RAM. A disadvantage of DRAM cards are that they lose their data if not continually refreshed, so the cards cannot be used to transfer data between machines. DRAM cards increase the memory size of the machine, which can provide a speed increase to (e.g.) MS-Windows applications.
As technology advances, it should be cost effective to put floppy drives, tape backups, serial/parallel ports, modems, and virtually all other computer peripherals on PCMCIA cards. PCMCIA has a good chance of sweeping past (current) portable computer usage, and onto the desktop, across virtually all computer architectures. The PCMCIA standard is still evolving, with the association pushing to ensure end-user compatibility. The cards are reliable, economical to manufacture, and interchangeable. For more information, contact PCMCIA (www.pcmcia.com).
Page 12 had an ad for Mookie's Place
BBS (mookie.relay.net).
Memory cards (usually Type 1 cards) were among the first peripherals designed to the PCMCIA card specification. Here we give an overview of the different memory card technologies, and discuss the impact that nonvolatile memory cards will have on conventional (rotating) hard disk drives.
As the cost of Flash cards falls with volume production, and their performance improves, SRAM and programmable PROM cards will probably become obsolete.
Programmers typically start development by loading their software onto UVEPROM cards, which they can reprogram over and over until the code is fully debugged. After the program is debugged, the less expensive OTP or mask ROM cards may be used for more economical volume distribution of the software to customers. Alternatively, a user could recycle last years UVEPROM card back to the manufacturer for reprogramming.
Current generation flash cards have error correction, wear-out prevention, bad sector lockout, and data recovery algorithms. Flash memory cards are starting to replace (rotating media) hard drives in selected applications.
Intel Flash cards use a NOR (Boolean Not-OR) based logic 28F010 128K x 8 (or larger) device. Toshiba Flash cards use a NAND (Boolean Not-AND) based logic IC (Integrated Circuit), with a much faster writing speed.
PCMCIA's ATA standard allows conventional hard disks, and solid-state memory, to have the same interface to the card's connector. Several companies are now offering PCMCIA-ATA "hard drive" memory cards. These (Type 1 size) cards emulate a hard drive, without requiring BIOS changes.
Currently, prices are much higher than a normal hard drive ($2000 for 40 MB). The price of ATA memory cards is expected to fall to almost the same level as magnetic media within a few years. I predict that (eventually) drives smaller than 1 GB will be ATA memory cards in the future, as the price of Flash memory drops.
Page 14 had ads for Floreat
(www.floreat.com),
and the Bust Out and Pacific Exchange BBSs.
Previous issues ( # 7 and # 8) described the process of connecting a DOS-based BBS to Usenet. While a DOS solution will work, there are other alternatives. In this issue and future issues, I will evaluate the use of other operating systems as a platform for a BBS.
In particular, I will explore UNIX and its work-alikes, running on an IBM 386/486/N86 based computer. I will note both the pluses and minuses so you can form your own opinion as to what will or won't work for you. Some features I will look for:
Today, a very large percentage of UNIX is coded in C, with a few kernel subroutines written in assembly language. Because the OS is written in a high-level language (compared to assembly language), it can be ported to a variety of CPU chips (Intel, Motorola, etc.). This accounts for a release of UNIX being available for almost every major computer platform.
The key features of UNIX (that are of benefit to BBS operators) are its internal design. Unix is multi-user and multitasking, and supports remote dial-ups via modems. This is included as part of the operating system, and is not an "extra charge" item. UNIX effortlessly handles concurrent multiple tasks with a minimum amount of hardware resources. Additional products such as Desqview (to support additional nodes or multitasking) are not necessary.
The cost of UNIX and its work-alikes varies widely. For a commercial release of UNIX, the cost can easily exceed $2000. To keep in line with our criteria of low-cost, the two UNIX operating systems we will be reviewing for use for a BBS are Coherent and LINUX. These packages are workalikes, meaning they have no AT&T source code, though they perform similarly to commercial UNIX.
The latest version for the 386/486 platform is 4.2. This 1-4 user version sells for $99.95. The unlimited user version sells for $299.95. Besides the operating system, a host of other programs and utilities are included. Programs included that are of importance to a BBS operator are complete UUCP utilities, a C compiler, awk, text editors and a couple of different shells (programming environments) for script programming.
The latest version of Coherent has support for SCO (Santa Cruz Operations software company) binaries, which has greatly increased the available application programs that can be used with it.
When using LINUX, it is very difficult to distinguish it from "real" UNIX (commercial and costly). Though SCO binaries cannot run under LINUX, a large number of applications are available for it from various sources. Some of these applications include X-Windows, GNU C/C++ compiler, UUCP communications support, X/Y/Zmodem, DOS emulation, and editors. Source code is available for almost all of the LINUX applications as well.
For those with Internet access, LINUX can be downloaded from different sites. Some BBSs have it available to be downloaded for free. The drawback of downloading LINUX, and its associated programs, is the size (15-50 MB), and time it takes to do so. For those who don't have Internet access, LINUX is available on CD-ROM, tape, or diskette. Prices range from $30 to $100.
I have found a couple of sites on the Internet that offer a variety of program files that handle most of our requirements. Some of the BBS programs I have found that have been ported for LINUX include PBBS, UniBBS, XBBS and MBox. These can be found at the Internet site sunsite.unc.edu (http://sunsite.unc.edu). (For Coherent, there is a collection of files available at raven.alaska.edu.)
The part proving to be difficult to locate, is an application that handles Fidonet message processing, in a way that is comparable to the wide variety of programs available for DOS. There has been some message traffic on Fidonet in the UNIX echo about such a package, and hopefully I will be able to track it down. Apparently it is a modified version of Binkley, which has been available for DOS in both binary and source code form for a number of years now.
Next month I'll get down to the nuts and bolts of hooking up our modems to Coherent (and LINUX) to answer the phone properly and present the user with a login prompt. Time to put on my technical writing hat, and get knee deep in setting up configuration files. I will try to cover getting a UUCP connection working so we can start receiving Usenet and Internet mail on our system. The article will be aimed at folks that have never done it before, so stay tuned...
Chat BBSs typically have 8 or more modems available, allowing multiple users to dial in simultaneously. A chat BBS typically offers a single phone number to dial. The phone company routes incoming calls (when the first one is busy) to the next available phone line, where the next modem answers the call.
Chat boards usually encourage the use of handles. A handle is a name you want to be called by, usually not your real name. Your login name will take on a personality to the other users as time goes on.
Chat boards usually have good email systems. Each user gets a mailbox, and each user has the ability to read, store, delete, and reply to mail. Your mailbox is private, and only you and the Sysop can read your mail. The Sysop usually respects the user's privacy. After you have read your mail, you can leave it alone and reply later.
Chat boards typically ask you a list of questions to get a picture of what you are like. Some chat BBSs, especially DLX software based ones, start off with a long questionnaire, as soon as you log in.
Questionnaires ask your gender, age, sexual preference, type of car you drive, what you look like, whether or not you smoke, and so on. If these questions seem intrusive, you can usually select the "none of your business" answer.
The purpose of the questionnaire is to give every user a personality that can be viewed by other users. If you get an email message from someone and you want to know a little more about him/her before answering, just browse his/her questionnaire.
Chat boards usually have optional Matchmaking features available. You can ask the for all the login names of the people whose questionnaires match yours to some degree. You can then browse them and decide whether or not to write to them.
When you select the chat option, you will be in there with anyone else who is online that has also selected the chat option. If no one is 'in chat' when you want to go in, you can enter chat alone and wait for others to drop in and join you.
When a user types a message on the keyboard and hits return, that message will appear on the screens of everyone else (who is in chat) along with a notation of who sent it. This way there can be true round-table discussions.
Chat BBSs are more likely than most to charge fees because of the cost of the extra computers, phone lines, and modems. Some boards charge a flat fee (e.g., $8 a month) and some charge a rate of (e.g., 25-50 cents per hour).
You're the Driver
Page 16 had ads for Just Computers!
(www.justcomp.com),
and the Night Watch BBS.
As you dial different BBSs, you may notice that some are part of a message network. This may include Usenet, FidoNet, RIME, or some other network. At times you may have dialed a BBS and were greeted with a message stating that netmail was being processed, and to call back later. This article is for those of you that have wondered how all of this works.
As part of each BBS, several message bases (sometimes called echoes or areas) exist that pertain to different issues. Let's say one of these message bases is oriented towards C programming. It so happens that both the San Francisco and the New York BBS, have a message base centered on C programming. On both systems, users are leaving messages relating to C programming.
On the BBS in New York, a user has left a question about the use of the latest version of the Acme C compiler. Unfortunately, none of the users on the New York BBS can assist in answering the question. However, there is a user on the San Francisco BBS that is familiar with the question left by the New York user. Due to the two BBSs being two separate systems, the user in New York will never get assistance.
If there was some way of being able to share messages between the two systems, users on both BBS's would benefit. This question has been asked before, and fortunately, it has been answered with messaging networks such as FidoNet and Usenet.
FidoNet is primarily a DOS-based messaging network and Usenet is primarily UNIX based. The concept of how messages are exchanged is very similar. To facilitate the exchange of messages between two systems, some steps need to occur.
At the simplest level, the entire message database of each system could be sent to the other BBS. This would be undesirable as it would result in messages being resent, and a good deal of processing time would be spent parsing out duplicate messages. A better alternative would be to gather or "scan" all the messages that have been posted by users of each of the two BBSs since the last gathering or scanning.
For example, on day one of the BBS, 15 messages are posted on the system in New York. At a certain time of the day, an "event" (discussed in more detail later) occurs. This reviews messages in the database, and determines that all 15 messages have never been sent to San Francisco before, so the 15 messages are sent.
On day two, 13 messages are posted to the message base in New York. At the event time, the message base is scanned, and only the last 13 messages will be sent to San Francisco, since the message database in San Francisco already has the first 15 messages. The 13 messages on day two (that were scanned) will be put into a "packet", just like the first 15 messages on day one.
This packet of messages is then compressed using a file compression utility. DOS based systems typically use PKZIP, though other compression programs can be used. The packet is then sent via modem to the other BBS in San Francisco.
The whole process of message scanning, packet creation, and the modem link, is done at pre-scheduled times, called events.
When the San Francisco BBS does the same thing (looking for new messages that need to be sent to New York), and the two systems connect with each other; their packets will be exchanged. After the packets are delivered to each other, the modems disconnect at both locations. The packets are then uncompressed and merged (or "tossed") into the appropriate message base on each BBS.
This example is a simple one, but closely approximates the process of how FidoNet / Usenet / Rime work. These networks do these same actions, on a much larger scale, as described previously.
Event:
Events are usually scheduled at times when the BBS is not likely to have users trying to call it. This is usually done very early in the morning (e.g., 1 AM -4AM). The reason for the early morning time is that when an event occurs, users will not be able to access the BBS (on single-line systems).
Depending on the size of packets that are received from other systems, an event can take anywhere from a minute to many hours. On our system, The Programmer's Corner, which has both FidoNet and Usenet message bases, approximately 3-4 hours each day are spent downloading packets of messages and then processing them. During this whole time, the BBS is unavailable to users.
The lack of BBS availability to users during these events can be a problem. Some Sysops get around this problem by using a network, and having additional computers do the event processing; while another computer is kept available for callers to access the BBS.
Other Sysops use a fast computer (with an ample amount of memory) and multitasking software such as Desqview. This solution works, but often the BBS can become sluggish in performance, for the caller accessing the system while messages are being processed. Processing message packets is disk drive intensive, and the speed of the system is impaired.
Message networks are a very exciting part of a BBS, as well as the Internet. Networks let you communicate with others all over the world.
Page 27 had an ad for UNIROM (www.unirom.com).
Page 28 was a full-page ad for PC-TEN
Page 29 was a full-page ad for PARS International Computer (www.pars.com)
Page 30 (back cover) was a full-page ad for TeleText Communications.
End of Issue 10. Go back, or to
Issue 11, or to
Mark's home page.