Leading Edge Model D
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The Leading Edge Model D was an IBM clone computer released by Leading Edge Hardware during or before 1986.
[edit] Hardware
The Model D featured an Intel 8088 microprocessor at 4.77MHz, although many had a switch in the back to run at 4.77MHz (normal) or 7.16MHz (high). Earlier models had no turbo switch and ran only at 4.77MHz, while a few of the later ones (seemingly very rare) were 7.16MHz only. Three models are known: DC-2011, DC-2010E, and DC-2011E. The "E" seems to correlate with the capability of running at 7.16MHz.
The motherboard came in eight different revisions: Revision 1, 5, 7, 8, CC1, CC2, WC1, and WC2. A list of motherboard part numbers and revision numbers can be found here. Revisions 1 through 7 were usually found in model DC-2011, with revisions 8 through WC2 being either in 2010E or 2011E. WC1 (presumably also WC2) is 7.16MHz only.
They came preinstalled with 512KB of RAM, user upgradeable to 640KB.[1] Some had the full 640KB preinstalled. Some of the later ones were upgradeable to 768KB.
Some models featured a monochrome/CGA selection switch, with a single port used for both modes. Some models had both a Monochrome and a CGA port, also with a switch to change modes (and ports).[1]
The Model D computers supported a special extended graphics mode, 640x200.
The buyer had the choice between a floppy disk model and a fixed disk (hard disk) model. The floppy disk model had one or two 360 KiB drives, so that the user could run MS-DOS programs on the primary drive and work with files on the secondary drive, if equipped.[1] The fixed disk model had one 360 KiB floppy drive and either a 10 MiB, 20 MiB, or 30 MiB hard disk.
The buyer also had a choice between an amber or a green monochrome CRT monitors.
The price was about $1600.
[edit] Software
The unit came with MS-DOS 3.10 or later, and a special edition of GW-BASIC to support the extended graphics mode.
It also came with a diagnostics disk. This disk contained a diagnostics program, and PARK.COM, a utility used to park the hard drive heads when the computer was to be moved. Most models also came with a word processing program developed by Leading Edge titled Leading Edge Word Processor, commonly referred to by its acronym 'LEWP'.
The computer supports the Microsoft Windows operating system up to version 3.0, as it is the last version of Windows to support Real Mode.
