Browse Prior Art Database

Using a Universal QIC-122 CODEC for Dynamic Linking of Object Code

IP.com Disclosure Number: IPCOM000108930D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 87K

Publishing Venue

IBM

Related People

Medan, Y: AUTHOR

Abstract

The problem solved by this disclosure is how to integrate a Dynamic Library Link (DLL) capability into a Universal QIC-122 Codec (see (*)). The novelty is in unifying the currently distinct processes of decompression and dynamic linking, enabling speedup and streamline of the loading process of an application program.

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Using a Universal QIC-122 CODEC for Dynamic Linking of Object Code

       The problem solved by this disclosure is how to integrate
a Dynamic Library Link (DLL) capability into a Universal QIC-122
Codec (see (*)).  The novelty is in unifying the currently distinct
processes of decompression and dynamic linking, enabling speedup and
streamline of the loading process of an application program.

      The new function is enabled by use of two specific control
codes of the Universal QIC-122 Codec that define a change in the
context of the decompression function and DLL module reference,
respectively.  If the new context is made accessible to the Codec,
either directly by hardware or indirectly by software that executes
on a host CPU, the standard QIC-122 decoding process may continue,
resulting in a fully executable application that includes all the DLL
components and references.

      DLL is an operating system (OS) level service that provides the
capability to link an executable program code dynamically rather than
storing large, pre-linked modules.  OS service modules which are
frequently used by many application software modules are grouped into
libraries that are dynamically accessed by the DLL function during
the loading process of the application for subsequent execution.  The
DLL function enables storage savings and in a general sense, can be
considered as a data compaction method.  In a typical LZ-1 type
compression scheme, such as QIC-122, it is assumed that a
byte-oriented input stream is to be encoded using a mixture of direct
coding, stating the actual value of the byte (raw byte) and indirect
coding using an offset and runlength values.  These point to a
previous instance of a given string (compressed byte) that is
contained in an adjacent history buffer.  The size of this buffer is
limited by practical considerations (2kb in the case of QIC-122) and,
therefore, a reference can be made to near term data.  Using the
notion of the Control Codes the state of a Universal QIC-122 Codec
can be changed to use contexts oth...