COMP 4—Power Tools for the Mind 1 Power Tools What’s in the Box? File Management & Windows Explorer What we’ll cover for this lecture topic: –Files and.

COMP 4—Power Tools for the Mind 1Power Tools

What’s in the Box?

File Management & Windows Explorer

What we’ll cover for this lecture topic:– Files and file management

• File types• Using files• File naming conventions• File organization/hierarchy• Future Trends

– Windows Explorer (tool)

Excellent tutorials! Very important concepts!



Files and File Management• Soon you will learn how five different kinds of data

can be represented in a computer.• How do we organize this data? It is all just a bunch

of 0s and 1s, no?– Yes, but we logically organize these 0s and 1s into files.

• Computer files are storage containers that hold all the 0s and 1s that represent all the data that belong to a single document or to a program.– DOCUMENT files– PROGRAM files (executable / source)

• Kept track of by Operating System (OS)

File types



• PROGRAM files (executable)– created by an programmer– called Executable files

• stored as machine code• ready to be executed by CPU (“compiled” code)• examples:

–application programs (Apps)–operating system programs (OS)–utilities (compression utility; backup utility; etc.)–some run at a user’s request; others at a program’s

request

• DOCUMENT files– created by an application program.– alphanumeric characters, numbers, pictures, sounds.



• PROGRAM files (source)– created by an programmer– called Source files

• usually stored as a readable text file (e.g. ASCII)• need translation before they can be executed by CPU• Example source files:

–program source files• Turing (e.g. later you will write Turing programs)• Java / C / C++

–script languages

• JavaScript / VisualBasic Script

–batch files

• bunch of commands stored in a text file.• automatically-executed batch file: “autoexec.bat”



Using filesFirst, two important digressions:

• Recall two-level storage:– Primary memory: “memory”– Secondary memory (auxiliary): “storage”

• Recall from Chapter 1-A (pp 11-13) that software also has two basic levels:– Applications software

like Word, Excel, or Quake– Systems software

the operating system



• You turn the computer ON:– System boot-up happens …– Power reaches chips on the main

circuit (mother board).– one chip is ROM memory that

contains a bootstrap program– it instructs the processor how to

copy (e.g. load) the operating system from the disk to the main memory

OK: so what happens in storage as we use computer files?



COMPUTER SYSTEM

Processor

Main MemoryInput Output

Auxiliary Storage- OS programs:

- Kernel (main supervisor)

- Application program loader

- Copy, Rename, Move, … routines

- APPS: Word Excel PPT Quake

- DATA files: Letter MyPic Budget

Volatile

Also provides inputs

Non-Volatile bootstrap program

Also savesoutputs

7



• What will happen INSIDE THE BOX whenWord is launched?

– Hint: Where is the MS WORD program stored even before you switched the computer on? Where must it be stored (be copied to) so that we can use it? Why?

– Remember: electronic memory is 1,000 to 100,000 times faster than electromechanical storage.

• Next, you want to create a new text document.– What’s in memory now?– Tell the computer to Start M.S. Word.

• Other terms for Starting: Launch; Load

Proc.

Main Memory

AuxiliaryStorage



• Exactly WHAT part of the computer system do you, the user, give this request to?

– Hint: what part of the computer system knows how to handle that request?

• In what ways can the user make that request?

Digression: What kind of file is MS Word? How do you know which apps are currently open?

Demo:Different ways to start a file.



– SO… MS Word provides a blank document window. You enter some text.

• Where is that text being stored?• What happens if the machine freezes up (crashes)?

Proc.

Main Memory

AuxiliaryStorage

– PROTECTON ?• SAVE the document to

a floppy or to the hard-drive!

• SAVE regularly!



– OK, so you save the text document.

Proc.

Main Memory

AuxiliaryStorage

• Which two things happens “in the box” when you Save it?

• What kind of file is it?• How many copies of that “file” are in existence at this

moment, and where are they stored?

• You make lots of changes to your document.– Where are those changes being stored?

• OK, finished with your changes. Whatare your 3 options here?• Save

– Replaces disk file with edited file.

• Just Close. Don’t save.– Why would you want to do this?

• Save As– Keep original: store newly edited file

under a different name



– Now you want to open (in addition) a data file you saved yesterday.

• First, where is it now? What happens “in the box” when you open it? Where is it then?

– You’re finished with the first document ...• What is the minimum I should close to free main memory?• Exactly what happens “in the box” when

you only close that document?• Why not quit the application?• What is the difference between

closing a document and closinga program? Proc.

Main Memory

AuxiliaryStorage



– You’re finished doing word processing for this computer session.

• What could you do now to free up memory? How?• Exactly what happens “in the box” when you do that?• How can you tell by looking at the desktop?

– What happens if I delete (‘recycle’) a file:• from the hard drive?

OS “moves” it to the recycle bin fromwhere can potentially be restoredlater.

• from a floppy disk?

Not moved to recycle bin. Cannoteasily be restored.

Proc.

Main Memory

AuxiliaryStorage



– In these previous examples• Things keep moving around from one type of

MEMORY to another.

• Later, we’ll examine more closely WHY we have different types of memory, what they are, and what they are good for.

Using Files interactive lab – see Lab-03

– What happens “in the box”: save, save As, move, copy, delete, etc.



Rules determined by the OS File naming conventions

(Win)– Windows 95/98/2000/XP:

• Up to 255 characters (including the extension). • Letters, numbers, most symbols except \ ? : “ < > |• Not case sensitive • Cannot use reserved words

– Filename extensions • Tells Windows OS what the file format is.• Some examples: (see text for more)

.exe .com --Executables that user can run

.sys .drv .dll --Executables that user cannot run

.doc .txt .xls --Text and spreadsheet file formats

.jpeg .gif .tif --Graphics file formats

.wav .mid .mp3 --Sound file formats

– Early PC days ….. Dreadful: “eight dot three”

Com1 Com2 Aux

Lpt1 Prn Nul

Folder view

UNHIDE



File naming conventions (Others)

Again, rules determined by O.S.– Mac OS

• Up to 31 characters • Letters, numbers, most symbols except :• Case sensitive • No reserved words

– Unix• From up to 14 to 256 characters (depends on version)• Letters, numbers, most symbols except \ ? “ < > | * ! @ # $ % ^ & ( ) { }

[ ] ;– no space allowed (sort of...); confuses the command line

• Case sensitive • Reserved words depend on version



• Traditional file organization– Early Operating systems for PCs:

• Remember what application you used; launch it first; then open data file.

• Organizing files: tendency to keep docs filed w/apps.– Is that particularly useful to USER? Why or why not?

File organization

• Document-centric file organization – Thanks to newer OSs:

• Open data file-- automatically launches app that created it.

• SO WHAT? Why is this more useful to the user?

“Documentcentricity”

Play With Extensions



LOGICAL file storage/organization

• OS keeps a directory for each disk:

– A list of files stored on that computer disk

– Where OS keeps track of each file (fname, date,

time, size…)

– Logical view of data storage.

– Later we will look into how the OS maintains

their physical location on the disk (clusters).



• Logical organization--way to organize &

visualize where folders and files are stored on a

disk….

– the OS helps us to do this

– incorporates a hierarchical organization….

– Metaphor: sideways tree…. (next slide)



Metaphor: Hierarchical file org. Trunk- Root directory- Disk drive or partition. Each ID’d by letter. What’s typical?

Branches- Subdirectories (aka: Folders): Can be directly under root directory (main branch).

Can be “nested” inside other subdirectories. (branch off main branch).

Leaves - Files

File specifications (paths):

D:\Homework\Comp 4\Lab 3 D:\Letters\Family\Mom.doc File spec for John.doc?

Study text reading carefully before doing Lab-03.



• File Management Tool in Windows 9x/Me/2000/XP

• Some useful shortcuts: Microsoft website

• More in Lab 3

Windows Explorer Demo



• Traditional: Hierarchical file org restrictive– Why?

Future Trends



• New Approach: Database style organization – Efficient search– Not a rigid hierarchy

• Desktop Search Tools (c. 2005)– Google Toolbar – Yahoo Toolbar– Microsoft – MSN Toolbar– Picasa (Google) for photos/videos

Future Trends



• Coming Soon: Database style organization inside the operating system– Apple: Tiger Spotlight (2005)– Windows: Longhorn WinFS (2006?)

Future Trends

COMP 4—Power Tools for the Mind 1 Power Tools What’s in the Box? File Management & Windows Explorer What we’ll cover for this lecture topic: –Files and.

Documents

power tools whats

computer files

program files source

executable files

program source files

cpu example source files

power reaches chips

file management file