The Pentagon (Пентагон) home computer was a clone of the British-made

Sinclair Sinclair may refer to: Places * Lake Sinclair, near Milledgeville, Georgia * Sinclair, Iowa * Sinclair, West Virginia * Sinclair, Wyoming * Sinclair Mills, British Columbia * Sinclair Township, Minnesota * Sinclair, Manitoba People * ...

ZX Spectrum 128. It was manufactured by amateurs in the former

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, following freely distributable documentation. Its

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was copied all over the ex-USSR in 1991-1996, which made it a widespread ZX Spectrum clone. The name "Pentagon" derives from the shape of the original PCB (Pentagon 48), with a diagonal cut in one of the corners. Many simple devices (upgrades) were invented to connect to the Pentagon with some soldering.

Versions

*Pentagon 48K (1989 by Vladimir Drozdov) *Pentagon 128K (1991) *Pentagon 128K 2+ (1991 by ATM) *Pentagon 128K 3+ (1993 by Solon) *Pentagon 1024SL v1.x (2005 by Alex Zhabin) *Pentagon-1024SL v2.x (2006 by Alex Zhabin) *Pentagon ver.2.666 (2009 by Alex Zhabin) The Pentagon 1024SL v2.3 included most of the upgrades of the standard Spectrum architecture, including 1024 KB

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, Beta 128 Disk Interface and ZX-BUS slots (especially for IDE and General Sound cards). This model also featured a "turbo" mode (7 MHz instead of the original's 3.50 MHz).

Upgrades from the original ZX Spectrum

* Extra RAM ranging from 256 KB to 4 MB * Several

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possibilities such as

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(usually named as ''SounDrive'') or DMA

UltraSound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...

* Additional video modes: 512x192 monochrome, 384x304, 256x192x15 (with no

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) * CMOS with persistent

real-time clock A real-time clock (RTC) is an electronic device (most often in the form of an integrated circuit) that measures the passage of time. Although the term often refers to the devices in personal computers, servers and embedded systems, RTCs are pr ...

* IDE Controller for

hard drives A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magne ...

* "

Turbo Mode On IBM PC compatible computers, the turbo button selects one of two run states: the default "turbo" speed or a reduced speed closer to the Intel 8086 CPU. It was relatively common on computers using the Intel 80286, Intel 80386 and Intel 804 ...

" that clocks the CPU up to 7 MHz

Versions

Upgrades from the original ZX Spectrum

References

External links