Optimize Available Memory Space For Successful Downloads; Support For File Compression; Effect Of Downloads On Existing Files And Data - VeriFone Vx810 Reference Manual

P D
ERFORMING OWNLOADS

Effect of Downloads on Existing Files and Data

Optimize Available
Memory Space for
Successful
Downloads
Support for File
Compression
Effect of
Downloads on
Existing Files
and Data
110
V X 810 R G
EFERENCE
One certificate file or signature file requires approximately 400 bytes of memory
space. The application designer must account for the extra memory required to
download and store these special files.
When planning your download procedure, carefully consider the total amount of
memory space required to store certificates and signature files and the application
files. In some cases, a considerable number of 400-byte signature files reside in
device memory at any given time. Here are some general guidelines to follow:
•
Know the size of available memory (SRAM and flash ROM) of the receiving
device; also in back-to-back downloads, know the size of available memory on
both the sending and receiving devices.
•
Know in advance how application files are redirected to SRAM or flash ROM
and to file groups other than the target group.
•
Defragment flash ROM memory before performing a download to optimize the
available space in the flash ROM file system.
•
Before performing a download, use the system mode menu selections to clear
the entire SRAM and flash ROM of a specific file group, as necessary, to
ensure proper use of available memory in the target group.
For information regarding file compression, refer to the Verix V Operating System
Programmers Manual, VPN 23230.
When downloading application files and data to a V
consideration is the effect of the download procedure on existing application files,
files used in the file authentication process, and device configuration settings
stored in CONFIG.SYS files in the receiving device. Here are some important
points:
•
If a file already exists in the target file group, the existing file is replaced with
the new file of the same name. (Files in separate file groups can have identical
names.)
•
Always download executable files (and any other files to logically protect
under VeriShield file authentication) with the certificates and signature files
required to authenticate them.
•
In full or partial application downloads, all CONFIG.SYS records on the
receiving device, both protected and non-protected (that is, beginning with * or
#), are retained. New CONFIG.SYS variables included in the download
package, including the *GO variable, selectively replace existing variables
with the same key name in the CONFIG.SYS file of the target group.
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