It:it files

Managing your Computer Desktop

Organisation of files

This course is all about managing data/information/knowledge with the help of computers.

They do so with the help of an:

1. Operating System (OS), examples of which include:
   1. Microsoft Windows: Windows 7.
   2. Unix: Mac OS X, Redhat Linux
   3. Mobile devices/SmartPhones: Symbian, Windows Mobile, Android, iOS (+ iTunes)
2. Access to which is controlled by authentication against User names/passwords and via Web-pages by the same authentication, and which serves to identify the author/curator of data and information so created.
3. Organisation: is historically be a metaphor based on Files or Documents which are located in Hierarchical Folders (Directories). Directories referred to as Home or My documents have special status for each authenticated user.
   • Files: adopt naming convention can use up to 256 characters, but with some caveats:
   1. do not use characters such as space, $, /, :, ? .
   2. If you are tempted to use a space, use the underscore _ instead!
   3. On Linux (only), Filenames are case sensitive. Often the cause of much confusion!
   • File Content/Data type: is normally (approximately) indicated by adding a 2-4 character extension after a period (.docx) to the name.
   1. This extension
      
      may or may not be visible. Chemical files reserve ~8 different extensions, so you may end up with up to 8 files with apparently the same name!
   2. Special types of file, used by the operating system, may be invisible by virtue of their name starting with a period.
   3. The (free text) content of a file may have been indexed and hence may become
      
      searchable by the utilities provided by the operating system.
   • File Metadata (Properties): Creation/Modification Dates, sizes, access permissions, "ownership", content, etc is also organised by the OS.
   • File Location is in a hierarchy and is located by searches using file metadata as criteria.
4. File Size: In "bytes" (approximately, 1 character = 1 byte, sometimes 2 bytes). 10⁶ bytes =~1 Mbyte, 10⁹ bytes = ~1 Gbyte, 10¹² bytes = ~1 Tbyte. Maximum size for any file normally 2 Gbyte (Windows) or very much larger (Linux, Mac OS X).
5. File Archives: A collection of Folders and Files which preserves the hierarchy and file metadata (.zip, .tar). A .docx file is in fact a (zip) archive
6. 
   File Storage (enterprise environment)
   • Permanent Data Storage, as files on:
     • Network Drives:
       1. Drive H Home directory (Desktop icon Home, capacity 1 Gbytes per user)
       2. Drive L: "Home" on Linux systems
       3. Drive M: Storage area for bibliographic libraries such as Mendeley.
       4. Drive R: Where files from departmental NMR Spectrometers are placed (read-only)
       5. Drive Z: Chemistry data-silo for temporary storage.
     • Local Hard Drive C: Not to be used except for temporary storage.
     • Removable media: memory sticks, iPods, CD-RW/DVD (capacity 1-120 Gbyte)
   • Temporary Data Storage, as
     • "clipboard" in "System Memory" (capacity not known by user, but probably < 10 Mbyte)
     • cache or temporary files, not normally seen by the user but can wreak havoc if corrupt!
7. File Usage: Data Files are created and exchanged using:
   • Combinations of programs, typically a Word processor (Word), a chemical drawing program (Chemdraw) and Bibliographic database (EndNote/Mendeley).
   • Data exchange between these programs using copy/paste via clipboards or via files (drag-n-drop, save/open or sync).

Managing your Location

All the above applies when you are connecting to your resources on campus (which by definition also includes South Kensington Halls of residence). If you are outside this catchment area, some IT services will not work unless you enter the campus virtually by switching on something called a VPN. These services include most Scientific journals and the important databases.