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Problem in framing or understanding the exact approach for the given specification

 
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Hi , I got a task to create a java program , but actually I am not able to understand what I need to do . I mean , there are some Filie System , flat file scenarios and space given . So please explain me what exactly I need to code and what is the actual requirement. The problem given as-
**I do not need the entire code .

A specification for a very simple file system stored inside a flat file (FS). There is an associated index file (FI) which
provides meta-data to the data inside the flat file (FS).

/* What is this FS and FI and what should I code here*/

FS:- FS cannot be larger than 1 MB. The entire space in FS is divided into blocks of 128 bytes.

/* FI details is given , but actually what they want me to code */
FI:- FI provides meta-data regarding what is stored in FS. Directories, sub-directories and files are supported. Files can be
binary or text which is marked in the meta-data. The following is a detailed description of FI –
FI consists of a sequence of entries or records. Each record (Record) is 48 bytes long. Each record has an index and is referred
by its index. There can be a max 8192 Records if each file is exactly one block long. Therefore FI can be at most 8192 x 48 =
~384KB in size. The structure of each Record is –

1 2 3 4 5
|-----------------|--|--|---|-------|

1 – Name (32 bytes)
2 – Attribs (2 bytes) Described below
3 – Directory Entry (2 bytes) – what is the parent directory of this record
4 – Size (4 bytes) – File size, 0 for Directory
5 – Blocks list (8 bytes)

Name – The file/dir name can be at most 32 bytes long. Only ascii alpha-numeric characters are allowed.
The only symbols allowed are - $ and .
A string shorter than 32 characters is terminated with an ascii value of 0.

Attributes – Only the relevant attributes are described here
1st bit – if set is a File else Dir
3rd bit – if set is a Text file else Binary

Dir Entry – The index of the parent’s Record in FI. The root entry has this value as 0.

Size – The actual size of the file (not the block count), always 0 for directories

Blocks list – Lists which blocks in FS holds the contents of this record. 8 bytes allows for 4 block indices to be specified
each of size 2 bytes. If a file is larger than 4 block sizes (i.e. larger than 512 bytes) then a chaining mechanism is used
where the last 2 bytes of the block from FD is used to point to the next block in FS. Suppose if the file is of 8 block
size, then the last 2 bytes of 4th block will point to 5th block and last 2 bytes of 5th block points to 6th block and so on.
Directories will not have any block entries.
The root directory always occupies Record[0].


/*If I only need to code the given problem , I can code but FI and FS is really creating a big problem*/
Problem
A] Write a class com.progress.test.FSReader which has a static read method and takes as its only argument a file path similar
to \files\abc.txt and returns a String of its contents.
If the path provided is not a file or not a text file null must be returned. No exceptions must be thrown.
Signature -> String com.progress.test.FSReader.read(String path)



Please explain me exactly what I need to code.
Thanks in advance.
 
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So, what is exactly the problem, you don't understand what "FS" and "FI" are? I guess FS stands for File System and FI for File Index. The whole assignment explains what those things are - FS is just a block of data, which can at most be 1 MB, and FI is a data structure that describes files in this little toy file system.

Are you doing a course? Ask your professor or course leader or your fellow students to explain it to you.
 
Author
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Looks like you're emulating a simplistic file system. I'm not sure where you're having a problem--perhaps if you ask a specific question, or post what code you have so far.
 
buntha Choudhary
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Actually I was not understanding that FI and FS were just an explanation.
I was thinking that I need to code or create a program of FI and FS .

Thanks .
 
David Newton
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You do, or at least could.
 
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hey bro..I also got a similar assignment, but I got the files FI.txt and FS.txt with it, which has the file structure and the file itself. Did you get that too?

Additionally I have been asked to send the output for file path \Progress\OpenEdge\OpenEdge.txt along with Source code.

I think there is some problem with the files that I got. No matter what path I enter the content is blank.

Did you too get the files FI.txt and FS.txt, can you please mail me yours at dceashish@gmail.com
 
David Newton
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Please BeForthrightWhenCrossPostingToOtherSites:

http://forums.sun.com/thread.jspa?threadID=5433502
 
David Newton
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From where are you getting this problem?
 
Ashishh Rawat
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I got this as part of a screening exercise of a company. Have to submit the code within two days. I didn't find the problem too complex, except that I couldn't get the right output
 
David Newton
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I guess it was complex enough, then.

Do you think it's ethical for us to help you write code that will help someone else decide whether or not to give you a job?

If I found out that someone I was hiring didn't do all the work themselves I would immediately eliminate them as a possible candidate.
 
Ashishh Rawat
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Quite true. But the fact is that I never asked anyone to write my code. I feel that the sample files I got to test my program somehow got corrupted. So, I am asking the owner of this post to send me the test files so that I can verify if that is the problem.
 
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