Table 108. typical gzip file compression results – Campbell Scientific CR1000 Measurement and Control System User Manual

Page 413

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Section 8. Operation

413

 

c) When prompted, set the archive format to “Gzip”.

d) Select

OK

.

The resultant file names will be of the type “myProgram.cr1.gz” and
“CR1000.Std.25.obj.gz”. Note that the file names end with “.gz”. The ".gz”
extension must be preceded with the original file extension (.cr1, .obj) as shown.

 

Q: How do I send a compressed file to the CR1000?

A: A Gzip compressed file can be sent to a CR1000 datalogger by clicking the
Send Program command in the datalogger support software

(p. 77).

Compressed

programs can also be sent using HTTP PUT to the CR1000 web server. The
CR1000 will not automatically decompress and use compressed files sent via File
Control
, FTP, or a low-level OS download; however, these files can be manually
decompressed by marking as Run Now using File Control, FileManage(), and
HTTP.

Note Compression has little effect on an encrypted program (see FileEncrypt()
in the CRBasic Editor Help), since the encryption process does not produce a
large number of repeatable byte patterns. Gzip has little effect on files that
already employ compression such as JPEG or MPEG-4.

Table 108. Typical Gzip File Compression Results

File

Original Size Bytes

Compressed Size Bytes

CR1000 operating system

1,753,976

671,626

Small program

2,600

1,113

Large program

32,157

7,085

 

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