Regarding Amdahl’s balanced system law

One of the paper titled “Rules of Thumb in Data Engineering” (Jim Gray et. el.) mentions some calculations based on Amdahl’s balanced system law. Link to paper: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/ms_tr_99_100_rules_of_thumb_in_data_engineering.pdf Initially, the paper provides some rules of thumb. “10. Amdahl’s revised balanced system law: A system needs 8 MIPS/MBpsIO, but the instruction rate and IO rate must … Read more

Difference between Sequential ,Direct and Random acess with their acess time

I’m stuck on a point while reading about these different accessing methods. As per author. Sequential access Memory is organized into units of data, called records.Access must be made in a specific linear sequence. I understand that it will take variable time to access due to sequential ordering. Direct Access individual blocks or records have … Read more

How can I formalize key value stores with set theory?

I’m currently developing a simple key-value NoSQL store and want to build its formal model. I found article about key value formalisation with category theory, but I’m interested are there some works about formalisation of key-value stores except category theory (I know we can use it for all, but…)? I want to use some more … Read more

What is the difference between storage media and storage devices [closed]

Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it’s on-topic for Computer Science Stack Exchange. Closed 7 years ago. Improve this question I am having a rather distressing confusion about whether storage media and storage devices are the same terms. I found on … Read more

Why is data stored on a flash disk irretrievable if the memory chip is cracked? [closed]

Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it’s on-topic for Computer Science Stack Exchange. Closed 7 years ago. Improve this question All data recovery companies, regardless of skill, unanimously say that if the memory chip of a device has just a hair … Read more

How are the number of bytes less than the number of pixels in an image?

Lets take, for example this jpeg image here The image there is 400 x 300, or 120000 pixels and The file size of the image (on my computer) is shown to be 65171 bytes. This means the computer stores about 2 pixels in every byte. How does it do this? Is it due to the … Read more

Is ROM primary memory or secondary memory?

According to this picture ROM is classified under Main Memory , but isn’t ROM a secondary storage because it’s external and non volatile ? Any clarification with reference links will be highly appreciated. Thank you. Answer The distinction between primary and secondary storage relies on several joint characteristics which the prototypical examples – RAM and … Read more