(The text from the image below has been copied into the spoiler below the image.)
[ You are not allowed to view attachments ]
Spoiler
Notes on compression ratio difference between ZIP and 7-ZIP.
I tend to use the standard Windows ZIP (using the built-in Windows compression tool) to compress old documents into an archive state, but where I still need to have those documents indexed/searchable. I use an iFilter to enable WDS (Windows Desktop Search) to search within .ZIP files.
Otherwise I tend to use 7-ZIP, which generally has much better file compression.
The HP Support utilities program for the new (refurbished) HP Pavilion I am currently setting up uses several directories of information. One is a folder holding the User Guides (C:\Program Files\HP\Documentation\platform_guides\ug).
The guides are all PDF documents.
There were 38 PDF files (one file for each of the 38 different languages catered for), each typically of about 2.2MB in size (with some occasional variation).
Wherever possible, I try to avoid littering a PC's hard drive with document files that are not required, because:
a. They take up client device space on a finite volume - space that could probably be better left empty for something more useful.
b. They can add to backup process CPU resources and duration and backup storage requirements.
c. They take up client CPU time - as I have WDS set to index document files (including PDF files).
I initially considered deleting them, but then decided against it. I reckoned that, if they were all in a single compressed file, then they would not take up too much space and would require less resources as a single file on backup (multiple file handling also takes more time). So I decided to compress them into a single file.
I only needed the English version - which was a 2.1MB file named 824463-001.pdf (the suffix -001 is apparently the language ID code used by HP for discriminating between languages (I am not familiar with whatever codification method they use for this ID).So, I selected the 37 "unwanted" (non-English) PDF files in the directory, and xplorer² showed me that they were 85.3MB in total volume.
Using Send To, I intended to send them to a 7-ZIP (7z) compressed file - i.e., rather than ZIP, as I didn't need WDS to search/index the documents) - but I was `a little preoccupied with my 6y/o son. who wanted me to help him with something and, by mistake, I sent them as a selected group to a ZIP archive.
That resulted in a compressed ZIP file of 61.1MB.
The compression saving was ((85.3-61.1)/85.3)*100=28.3705% I then realised my mistake and at the same time I observed that that compression didn't look like a very significant compression ratio (85.3:61.1).
Curious to see the comparison, I then sent the same files to a 7-ZIP (7z) compressed file.
That resulted in a compressed 7z file of 26.4MB. The compression saving was ((85.3-26.4)/85.3)*100=69.0504% So, 7-ZIP's compression was 69.1-28.4=40.7% greater for the same set of documents.
This was a timely reminder to me of how significantly more efficient a compression algorithm 7-ZIP had than that of the standard ZIP.
Obviously compression rates could vary depending on the types of file being compressed, but I had forgotten that the differential between ZIP and 7-ZIP could be that significant!