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Menu Level
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Why Needed
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Description
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| 1 Split |
SubSub |
Some Files are
- Too big to send by email
- Too big to store on USB FAT32 stick
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- Splits by a designated size
- incorporates a SHA1 Hash to enable the files to be checked
- extension -
- 0slar holds split file details
- Number of Splits
- Slit size
- last Split size
- SHA1 for each split
- 1slar to "last Number"slar holds data
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| 2 Join |
SubSub |
Need to joins files that have been split by "1 Split" routine
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- Joins Files that have been split by "1 Split"
- Checks that files have not been altered using a stored SHA1
hash
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| 3 Check Split
Files |
SubSub |
Need to check FIles split by "1 Split" routine have not altered |
- Checks that files have not been altered using a stored SHA1
hash in the split files
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| Three functions
(Split, Join, Check Split Files) above are related |
| 4 Compress
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SubSub |
Some Files are
- Too big to send by email
- Too big to store on USB FAT32 stick
- Need compressing to take up smaller space
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- Compresses files
- Compresses and splits files if the file is too large
- extension
- ezp - compress for files less than 1000000
- elzp - compress for files lager than 1Mb
- 0lezp split compression
- splits files into 1000000 parts with remainder
- Has header
- size
- name
- number of parts
- SHA0 of file
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| 5
De-Compress |
SubSub |
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- De-compresses files according to extension
- Checks that stored Hash of original file matches hash of
decompressed file
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| 6
Check Compressed Files |
SubSub |
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- Checks that stored Hash of original file matches hash of
decompressed file
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| 7
Predict Compressed File Size |
SubSub |
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- Makes an estimate of file if it were to compress.
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| 8
Predict Uncompressed File Sizes |
SubSub |
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- Make an estimate of what space a compressed file would take
up
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| The five functions (Compress, De-Compress,
Check Compressed Files, Predict Compressed File Size, Predict
Uncompressed File Size) above are related |
| 9 Join Files |
SubSub |
- All Files are allocated space on a hard drive.
- Space files occupy is determined by sector size
- Some File systems make allowance for sector size when
allocating file pointers, but not all file systems do this
- By joining lots of small files together space can be saved on
hard drive
- Joined files
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- Join Files can be left as they are
- Joined Files can be Compressed
- Joined Files can be encrypted
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| a Separate |
SubSub |
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- Separate out files from joined files
- Separate out files from joined files which have been
compressed
- Separate out files from joined files which have been encrypted
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| The two functions (Join Files, Separate)
above are related |