Internal and External fragmentation

Question

Consider $6$ memory partitions of sizes $200$ $\text{KB}$, $400$ $\text{KB}$, $600$ $\text{KB}$, $500$ $\text{KB}$, $300$ $\text{KB}$and $250$ $\text{KB}$, where $\text{KB}$refers to $\text{kilobyte}$. These partitions need to be allotted to four processes of sizes $357$ $\text{KB}$, $210$ $\text{KB}$, $468$ $\text{KB}$, $491$ $\text{KB}$in that order. If the best-fit algorithm is used, Amount of internal and external fragmentation occurs is?

 

I am getting internal fragmentation as 124 KB, whereas nothing can be say about external fragmentation as we don't know what will be the size of the next coming process. And external fragmentation can only be calculated when we have the information about free memory slots and the process size whose size must be greater than Max free slot size.

Someone verify it.

Comments

in question they have said that the process are comming in particular order  @Gurdeep

then according to you all process should be collected at one place then applied best fit strategy

---

In these type of questions ,by default do we consider fixed size partitioning or variable sized partitioning

---

Why will it wait? The block is already filled & no further partitions can be done.

It should go to 600k block partition

Then, IF = 224KB

EF= 500KB

Answer 1

357 fit into 400

210 fit into 250

468 fit into 500

now 491 should be fit into 500 not in  600 because of best fit is used  

so 491  will wait until 500 will become  empty and after that it will go into 500

so internal fragmentation=124 KB

we know very well that when there is a internal fragmentation than there will be external fragmentation

than  EF>=124 KB

why EF>= 124 ? because the space  124 KB which remained left can not be allocated to any other because it is static partition (lets consider a senario in which  all the remaining slot that is is completely filled by the three more process 200 ,300,600   now take  one more process  1 KB. we can not allocate this even through space is available .here main thing is that the space 124 can not be allocated so i count it in EF)

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

but answer will be different if it was dynamic partation

at this case there will be no internal fragmentation and we can not say nothing about EF

Comments

@gurdeep saini

Plz explain in detail how external fragmentation will be 124 as we don't know the size of upcoming process?