Английский для бакалавров. Валиулина Т.Н - 278 стр.

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The system unit contains a 16 / 24 / 32 - bit microprocessor, the two diskette
drives housed in a single table - top unit. The system unit is powered from a standard
230 - volt ac grounded wall outlet.
The computer system has two modes: alphanumeric (A / N) or text mode and
graphics mode.
A few words about A / N mode.
In text mode, it supports either a 40 / 25 or an 80 / 25 display format. Each
character is format in an 8 / 8 character box. Characters can be black or white or
displayed in colour with 8 background colours and 16 foreground colours. Multiple
pages of text may also be stored in the adapter.
The display adapter card contains ROM character generator that provides 256
characters for displaying on the screen. In addition to the standard 96 ASCII
characters, there are special characters for supporting games and text processing, plus
international character and symbols, line graphics, scientific notations and Greek
characters.
Each display character position is defined by two bytes in the adapter 16K
RAM. One byte is for the display character code byte, which is the ASCII character
code and the second byte is the attribute.
Thus, for the 80 column per 25 rows display, it's required 4000 bytes.
The second possible mode is a graphics mode. The adapter card has two
graphics modes - a 320 / 200 four colour mode and a 640 / 200 monochrome mode. In
the 320 / 200 mode, each dot on the screen can be programmed with any of the four
colours.
The 320 / 200 medium resolution mode uses 16000 bytes of memory,
organised in 4 pixels horizontally per byte. The screen is divided into two buffers,
the first 8K buffer holding data for the even lines and the second hold data for the odd
lines. Each pixel on the screen is defined by two bits
The 640 / 200 high resolution mode requires 16Kb. Every bit is mapped to a
pixel on the screen. So, one byte will represent 8 pixels on the screen.
The personal computer can be connected to either 84-keys or 101-keys
keyboard.
The 84-keys keyboard is a AT / XT compatible keyboard. It is changeable to
the AT or XT by selective switch at the back of the keyboard.
Various languages keyboards are available: English, German, Russian and
others.
The 101-keys keyboard with an outside is to select XT or AT mode. It is
basically an intelligent and detachable keyboard.
Vocabulary

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