Poisk-2 is an analogue of the IBM PC/XT, compatible with PC/XT both at the software and hardware levels. Built on the domestic element base.Produced by the Kyiv NPO Electronmash. Initially, educational institutions of the USSR became the main consumers of this computer.
Motherboard PC "Poisk-2"
Prototype with different component placement
Specifications:
Processor - KR1810VM86M, 8 MHz. It was possible to complete the mathematical coprocessor K1810VM87B.
RAM - 640-2048 KB on K565RU7 and K565RU5. An interesting feature of the computer was the ability to automatically disable those blocks of RAM that did not pass the memory test. In one RAM block (4 blocks in total) there were K565RU7 or K565RU5 microcircuits, which was 512 Kb or 128 Kb, respectively.
RAM beyond 1MB was used as EMS.
ROM - 16 KB.
Video adapter - Hercules and Extended CGA video adapters (32K video memory, additional video modes non-standard for CGA) of our own design, EGA video adapter of our own production, but on a foreign CityGate D10 chipset, as well as VGA manufactured by Realtek, could be installed.
The presence of an RTC chip and CMOS memory, the system was configured using the BIOS Setup program, and not using jumpers, as in the classic XT.
Hard and floppy disk controller based on the i82064 and i8272 chips, allowing you to connect one MFM / RLE hard disk and up to two 5.25" 1.2-MB or 3.5" 1.44-MB floppy drives.
Port controller, with two COM ports and one LPT port.
Quite often, these PCs were used as “teaching” ones when building computer classes based on the Poisk-1 system; independent computer classes were also built on their basis.
K1810VM86 CPU is a Soviet single-chip 16-bit microprocessor that performs about 2 million operations per second. Synchronized with a clock frequency of 2 to 5 MHz. It is an analogue of the Intel 8086 microprocessor. Joint development of the Kyiv Research Institute of Microdevices, the Electronpribor plant (Fryazino) and the Rodon plant (Ivano-Frankivsk)[1].
It is included in the microprocessor kit of the KR1810 series, designed for building a microcomputer.
It has a 20-bit address bus, which allows direct addressing of 1 MB of external memory. The memory address space area is divided into 64 KB segments. Such a memory organization provides a more complex mechanism for calculating physical addresses compared to a linear address space, however, it made it possible to ensure easy portability of code from 8-bit microprocessors of previous generations (Intel 8080 and its Soviet analogue KR580VM80A). The address bus and the data bus are multiplexed. When organizing computing systems, they need to be separated (latch registers). The microprocessor can access both memory and external devices.
When accessing external devices, 16 minor lines of the address bus are used. Therefore, you can connect 64K 8-bit external devices or 32K 16-bit. The microprocessor has a multi-level interrupt system: 256 interrupt vectors.