Maximum file size in os

Question

How to calculate  MAXIMUM POSSIBLE FILE SIZE and TOTAL POSSIBLE FILE SIZE in unix os.

--------------------------------------------------------------------------------------

My approach is

Maximum possible file size=$[\frac{DB size}{DBA}]^{n}$  .Here 'n' is no of n indirect block addresses.

Total possible file size=$[#direct dba's+DB size/DBA.+[DB size/DBA]^{2}+......]* DB size$

Comments

I think they should be same because you can distribute the file into different blocks. Correct me if wrong. ANy ref citing the difference?

Now, max file size depends upon the fan-out and level of indirection.

Let,  block ptr size= Bptr and block size = B

Thus, if there is single level of indirection, fan-out at height=1 is [B/Bptr]

Thus, max file size = [B/Bptr] * B

---

i saw some where in test series

Max file size=Max{#direct dba,single indirect,double indirect}*DBSize.

Total =summation of all addresses.

---

I have also seen that in made easy test series and made easy question bank. But both are same are to be calculated by summation formula only.

---

No,in some test maxfile size is calculated as above formula and total file size is summation formula.

---

That is what I am saying bro, I have also observed that but if such question will be asked in gate I am going to use summation formula only. This has been discussed before also on gateoverflow and there also everyone said to use summation formula. If options are given then it is possible that singly and direct block address gives values in kb where as triply in Gb in that case we ignore kb values bcoz of options.

---

Yes, it should be summation.

---

k bro,thanks @rahul and @sushant