Browse Prior Art Database

Memory-Optimized Font Data Management in the Virtual Memory System

IP.com Disclosure Number: IPCOM000118128D
Original Publication Date: 1996-Oct-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 158K

Publishing Venue

IBM

Related People

Kawai, K: AUTHOR [+3]

Abstract

Disclosed is a memory-optimized font data management advanced operating system which supports the virtual memory system by paging function. It is especially effective for a large character set, like double byte character set or unicode. It rearranges the order of the characters by frequency of use, then puts font data of these characters as read-only flat data in this rearranged order, so that the virtual memory system always loads characters of high frequency and rarely loads characters of low frequency in the real memory. It also counts the frequency of accessed characters dynamically so that the operating system can optimize this system for each user when it shuts itself down.

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Memory-Optimized Font Data Management in the Virtual Memory System

      Disclosed is a memory-optimized font data management advanced
operating system which supports the virtual memory system by paging
function.  It is especially effective for a large character set, like
double byte character set or unicode.  It rearranges the order of the
characters by frequency of use, then puts font data of these
characters as read-only flat data in this rearranged order, so that
the virtual memory system always loads characters of high frequency
and rarely loads characters of low frequency in the real memory.  It
also counts the frequency of accessed characters dynamically so that
the operating system can optimize this system for each user when it
shuts itself down.

      The Figure shows how font data of characters is stored in the
hard disk drive, and how it is loaded in the real memory.  All of the
font data of characters is stored in one read-only-file in rearranged
order.  This read-only-file is loaded in the virtual memory at the
boot time.  The whole of font data of characters behaves itself to
exist in the memory, but actually the operating system does not spend
any real memory for it at this time.  When the operating system needs
the font data of characters to write to the video memory, it converts
the code point of the characters to rearranged code point by using
the remap table.  Then the operating system calculates the address of
the font data of characters...