Acorn BBC Master 65C102, Руководство пользователя

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To use either HiBASIC or HiEDIT, insert the 65C102 support disc into
the disc drive and enter:
*HiBASIC <RETURN>
(or)
*HiEDIT <RETURN>
depending on the language you wish to use.
Printer buffer utility
On the 65C102 Support Disc, along with HiBASIC and HiEDIT, you will
find a file called BUFFER. •
A buffer is an area of RAM that is used as a 'holding area' for data
that is in transit between the microcomputer and an external device.
The RAM may be part of either the microcomputer, or the external
device, and is part of the communications pathway through which the
two devices communicate.
The size of a particular buffer can make a considerable difference to
the speed and efficiency of a given data transfer. In the case of the
microcomputers' printer buffer, there is a 256 byte area of RAM
allocated to this purpose. This means that as soon as the
microcomputer has transmitted 256 bytes of data more than the printer
has accepted, the buffer will become full, and the microcomputer will
be forced to wait until more space becomes available in the printer
buffer.
The length of time the computer, and therefore the operator, spends
waiting is dependant upon three things:
a) The speed at which the printer can print
b) The size of the recieve buffer contained within the printer
c) The size of the transmit buffer in the microcomputer
Both a) and b) are determined by the design of the printer and are
not easily changed; the size of the default printer buffer in the
microcomputer is also fixed. It is however possible to re—allocate
the area of the microcomputers' memory to be used as a printer
buffer; this is the function of the printer buffer utility.
This utility provides you with an approximately 24 Kbyte buffer in
the I/O processor for use with your currently selected printer. This
dramatic increase in buffer size means that the computer will not
have to wait for the printer unless the data to be printed exceeds 24
Kbytes. In the instance of a text file, this may be considered to be
roughly equivalent to 24 A4 pages of text, sufficient to hold the
entire textual content of this manual with room to spare!
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