The ALL Card AT1 The All Card AT1 is a general purpose memory card with multifunction capabilities designed for the IBM Personal Computer, PC, XT and compatibles. It features a serial port with four variable addresses, a real time clock/calendar with battery backup, and memory expansion using 64K or 256 DRAM chips. The ALL Card AT1/M provides the same capabilities as the AT1, but will provide up to 10 megabytes of RAM memory, which may be used as conventional PC memory, extended memory, or a combination of both. The AT1 may be upgraded to an AT1/M by purchasing the optional MMU-1 (memory management unit) module. The memory management unit option increases the address space of the 8088 CPU on the PC from 1 megabyte to 10 megabytes. The amount of RAM memory directly addressable by DOS may be increased from 655,360 bytes to 974,848 bytes when the MMU is installed. The additional extended memory beyond one megabyte may be used for a variety of purposes. For example, under DOS this extended memory can be used for RAM disk, Expanded Memory Specifications (such as the Lotus/Intel/Microsoft EMS) and multi-user/multi- tasking systems where each user or task can be provided with their own protected 1 megabyte of RAM. The AT1/M comes with support software to enhance its capabilities. There are system files, utility programs and text files included, and these files are discussed in detail in the ALL/MOS Software Reference Manual. Segment Address Number of Segment 0 0 - 64K 1 64 - 128K 2 128 - 192K 3 192 - 256K 4 256 - 320K 5 320 - 384K 6 384 - 448K 7 448 - 512K 8 512 - 576K 9 576 - 640K A 640 - 704K B 704 - 768K C 768 - 832K D 832 - 896K E 896 - 960K F 960 - 1024K On a standard PC, memory may only be installed in Segments 0 through 9, providing an upper limit of 640k of addressable memory without using sophisticated memory management techniques. The top six segments of memory, Segments A through F (a total of 384k), were originally reserved for use by video RAM, ROM BIOS, the hard disk option ROM, and other hardware which IBM planned to produce at some future date. Although a total 384k of memory is reserved for special use, only a small amount is actually used. DOS allows the user to address 640k of memory, but the processor is capable of addressing 1024k of memory. Because of the 640k restriction, approximately thirty-five percent of the address space of the CPU is wasted. The MMU works to free up most of that wasted memory. The ALL CARD uses a proprietary MMU (Memory Management Unit) chip to extend the address capabilites of the 8088 CPU from 1MB to 10MB. The MMU intercedes between the 8088 CPU and its memory. A mapping table is used to convert any 20 bit address put out by the 8088 CPU to a 24 bit address. The high four bits of the resulting address is used to determine which area of memory is being addressed. The lowest megabyte of address space is connected to the conventional address space of the 8088 CPU.Subsequent megabytes of address space are connected to the extended memory provided by the ALL CARD. Through the mapping table, any contiguous 4k of the 8088's logical address space may be connected to any 4k of physical address space within the 10 megabytes of address space provided by the MMU. The MMU is thus able to rearrange what the 8088 CPU sees within its logical address space. Before DOS can address 952k of contiguous memory, the reserved areas of memory in Segments A through F must be moved out of the way. Since the MMU is able to map memory within the conventional address space of the 8088, video memory, BIOS and any other special memory areas may be mapped up to the high end of memory (Segment F) thereby freeing up Segments A through E for use as RAM memory. Memory from the ALL CARD is then mapped into Segments A through E. The CPU will then see contiguous memory in Segments 0 through E. Extended memory may also be mapped in to fill any uninstalled memory in Segments 0 through 9. DOS is able to use the resulting 952k of memory without modification. In turn, applications which currently run in 640k can use the additional DOS memory provided by the MMU. Although strict DOS programming rules discourage applications from directly accessing memory above the 640k mark, some programs do write directly to video memory, because the video support provided by DOS through BIOS is too slow for video intensive applications. Most applications will run in a 952k DOS environment without modification. Those applications which do write directly to video require minor modifications to run in a 952k environment. A utility called ALLPREP program is provided to make the needed modifications to those programs and its use is easy and also has an undo feature. Before starting installation you are directed to run the install program. This is not your normal installation program. This program allows you to answer questions about your system and the configuration that your are interested in using, and provides you with a picture on your monitor of just where on the ALLCARD sections are located. This provides you with detailed instructions and a better understanding of the hardware. I have never used a program like this and found it real easy to use. One word of caution, rename your CONFIG.SYS and AUTOEXEC.BAT prior to running the install program if you have special applications installed! Installation of the board will take about twenty minutes. The hardest part is taking out the CPU (8088) chip, and the co- processor if one is installed. This/these chip(s) are installed on the ALLCARD and a ribbon cable plug-in module is inserted into the socket which the CPU (8088) was installed. When this is completed, you are ready to re-boot the system. To see the results of your installating run CHKDSK and watch the results. Since there are many ways to use additional memory you are given a great many options. Ram disks, print spoolers and when using multi-tasking software (I only have DoubleDos and Desqview) 704k for each application. I have used this board for over two months and have never had a problem that I could attribute to the ALLCARD. I have an IRMA board installed and still didn't have any problems. When used in the EMS mode, it is at lease four times faster then either the RAMPAGE of the ABOVEBOARD. This is because much larger pages swapping is used with the ALLCARD. I am using an original PC-XT with and AST 384k multifunction card and a NEC V20. The board has 2MB installed and with the expansion module will hold 10MBs. Since 64k (ha ha), 256k, and 1MB chips can be used, the main board will hold 4MB. The one I am using has 1 MB (w/256k chips) on the main board and one set of 1MB chips on the daughter board. I was also given a battery backup for the ram disk as well as an AC adapter. Since the decision to have battery/AC backup must have been a late one the back of the ALLCARD has two small plug in slots that look crudely hand made, however I have seen a picture of the product that will be sold and it is a nice setup. The ALLCARD with the daughter board, battery/AC backup, without memory will sell for somthing like $500 to $650. Also in the mill is an AT ALLCARD with both un-protected and protected mode. Additional information can be received by writing or calling: ALL Computers Inc. 102 Bloor Street West Sutie 1200 Toronto, Ontario CANADA M5S 1M9 (416) 960-0111