u/Embarrassed_Grab6901

I do not quite remember from where I get this, but I got it few months earlier from an university's slide.

Array Processor:

Instruction operates on multiple data elements at the same time using different spaces.

Vector processor:

Instruction operates on multiple data elements at consecutive time in the same space.

There is a pic of the code being ran and showing the difference in Array Processor and Vector Processor as well...that I copied without much understanding in my notebook. Hoping to understand it later by asking here. But forgot about it.

https://imgur.com/a/ZiSGXlu

This is what I understand:

Optimistic concurrency control protocols are based on the assumption that the majority of the database operations do not conflict. Here the transaction goes through the three phases:

• read phase

• validation phase

• write phase

In read phase:

• transaction reads the database

• makes necessary changes to database values in a private copy of the database.

In validation phase:

• DBMS validates whether the changes that are made to the private copy of the database will violate serializability and consistency of the database. If in case they are violated, transaction is aborted and restarted. Otherwise, the transaction will proceed to write phase.

In the write phase:

The changes done to private copy of the database are made permanent.

You might be wondering you know this much then what are you not getting. I will show you the part from the book that I do not quite get.

I am taking two references: Coulouris et al distributed system and Conolly et al DBMS.

Conolly et al part that I do not understand:

I did not have colouris et al pdf at the moment. Just 1 topic 1 question.