What is a Virtual Disk ?
Virtual disks are solid state devices that directly replace
Floppy or Hard disk drives. In environments that have
vibration, large temperature differentials, and dust, disk
drives have short life spans and high failure rates.Because
Virtual disks use electronic components instead of magnetic
media for data storage, Virtual disks are much hardier than
disk drives and endure these environments much better. Also
virtual disk drives have a much faster access time than
conventional disk drives. If speed is a consideration,
consider a virtual disk.
Virtual Disk Operation
Acqutek's PM-Series cards are bootable virtual-disk cards.
They can be used as 256KB to 8MB disk drives. All PM-Series
cards can be configured as RAM based or ROM based
virtual-disks or as a combination of both.
The RAM-based virtual disk card uses a battery to keep data
from being lost when a system is powered down. This enables
the RAM-based card to retain information for periods of up to
a half year without power from the system. When system power is
returned, a charge circuit recharges the battery for the next
time it may be needed. Because the memory components are RAM,
data can be written to or read from just like a standard disk
drive.
The ROM-based virtual disk card has no need for batteries
because ROM is a more permanent type of memory. However, much
more is involved when data needs to be stored and not just
recalled. For example if data needs to be updated on an
EPROM, it can only be erased by an ultraviolet EPROM
eraser.(FLASH EPROMs are an exception) This means the virtual
disk has to be removed from the system and the EPROMs have to
be removed from the virtual disk. It is a very time consuming
process.
RAM (SRAM)
SRAM is Static Random Access Memory. This is a
volatile type of memory that can be read from and
written to many times. However, because it is
volatile, all data is lost that is stored in RAM when
the system power is down. The PM-series use a
rechargeable battery to backup the data stored in the
SRAM.
ROM (EPROM/Flash EPROM)
ROM is Read Only Memory. This is a static memory that
retains data even when system power goes down.
However once data is "burned" onto a ROM it cannot be
written to again. The user can "Read Only" from this
"Memory".
Flash EPROMs are a special type of EPROM that can be
erased using system power. As a result a virtual disk
with Flash EPROMs can erase the ROM and reprogram it
without removing the card or chips from the system.
However, Flash EPROMs are more expensive than standard
ultraviolet erasable ERPOMs. Users have to weigh the
options.
Many users prefer a virtual disk with a combination of
RAM and ROM. Important unchanging data, like the DOS
system, is loaded on ROM, while transient data is
stored on RAM.
PC-DOS 6.3 : IBM PC DOS 6.3 License For Virtual Disk Cards
The IBM PC-DOS 6.3 can be bundled with any Virtual Disk card
or CPU card purchased. There are 2 versions available. The
standard PC-DOS includes all PC-DOS files .The ROM version
PC-DOS includes only system boot files - IBMBIO.COM,
IBMDOS.COM, COMMAND.COM and FORMAT.COM.
IFD-series : 1.8", 2.5", 3.5" IDE Flash Disk
The IDE Dlash Disk provides reliable solution in packages to fit
conventional drive bay and with a very flexible capacity that
you will not waste your money. IDE Flash Disk is an IDE Disk
that based on Flash Technology. The IDE Flash Disk is
available in storage capacity ranging from 4MB to 512MB.
PM-7008 : Low Cost, 256/512KB Virtual Disk Card
The PM-7008 is a low cost half size virtual disk card. This
card has 8 28-pin DIP sockets that will accommodate 256K bit
SRAM (62256) or 512K bit EPROM (27512), therefore the maximum
capacity of PM-7008 is 256KB/512KB. Up to 4 PM-7008 can be
installed in a single computer.
PM-8002 : Low Cost, 1/2MB, Read-Only Virtual Disk Card
The PM-8002 is a Read-Only virtual disk card. This card has 2
32-pin DIP sockets that will accommodate 1M bit (27010) or 2M
bit (27020) or 4M bit (27040) chips, therefore the maximum
capacity of PM-8002 is 1M byte. The PM-8002 is a cost saving
solution for your applications.
PM-8008 : High Capacity 4/8MB Virtual Disk Card
The PM-8008 is a high capacity half sized virtual disk card.
It accommodates 8 1Mbit SRAM or 1/2/4Mbit EPROM or Flash
EPROM.
PM-8028 : Virtual Disk, 2/4MB Mono Graphics Display, & Printer Card
The PM-8028 is a Virtual disk card with monographics display
and printer I/F. This half size card accommodates 4 1Mbit
SRAM chips or 1/2/4Mbit EPROM or Flash EPROM.
PM-9008A : High Capacity 8/16MB Virtual Disk Card
The PM-9008A is a ultra high capacity half sized virtual disk
card. It can accommodate up to 8 1Mbit or 4Mbit SRAM chips or
1/2/4Mbit EPROM or Flash EPROM.
PM-i386XC : 386SX-40 All-in-one CPU Card with 1.5M/3MB Virtual Disk
The PM-i386XC-40 and PM-i486XC-40 are half-sized 386SX and
486SLC cards that run at 40MHz and can have up to 16MB of
DRAM. The card has 2 serial I/F, one printer I/F, HDD and FDD
I/F, an on-board Watch-Dog timer, a Buzzer and a battery
backed-up Real Time Clock. It comes with AMI BIOS. The
PM-i386XC-40/PM-i486XC-40 is equipped with three 32-pin sockets
which accommodate 1/4M bit SRAM, 1/2/4/8M bit EPROM and 1/2/4M
bit Flash EPROM. This allows the PM-i386XC-40/PM-i486XC-40 to
feature a 384KB, 768KB, 1.5MB or 3MB virtual disk drive.
PM-i486DX : 486DX/5x86 All-in-one CPU Card with 1.5M/3MB Virtual Disk
The PM-i486DX is half-sized 486DX or 5x86 all-in-one CPU card.
The card has 2 serial I/F, one printer I/F, HDD and FDD I/F,
an on-board Watch-Dog timer, a Buzzer and a battery backed
Real Time Clock. It comes with AMI BIOS. The PM-i486DX is
equipped with three 32-pin sockets which accommodate 1/4M bit SRAM,
1/2/4/8M bit EPROM and 1/2/4M bit Flash EPROM. This allows
the PM-i486DX to feature a 384KB, 768KB, 1.5MB or 3MB virtual
disk drive.
MK-V316 : PC/104 V-Disk and Digital I/O Expansion
The MK-V316 and MK-V324 are Virtual Disks and Digital I/O
expansion board for PM-i386XC and PM-i486DX. It provides
three Virtual disk memory sockets which double the V-disk
capacity of the PM-i386XC and PM-i486DX. It also provides 24
bits of digital I/O which can be connected to a variety of XDI
expansion boards.
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