is a comprehensive book on getting a job at a top tech company, while focuses on dev interviews and does this for PMs.
CareerCup's interview videos give you a real-life look at technical interviews. In these unscripted videos, watch how other candidates handle tough questions and how the interviewer thinks about their performance.
Most engineers make critical mistakes on their resumes -- we can fix your resume with our custom resume review service. And, we use fellow engineers as our resume reviewers, so you can be sure that we "get" what you're saying.
Our Mock Interviews will be conducted "in character" just like a real interview, and can focus on whatever topics you want. All our interviewers have worked for Microsoft, Google or Amazon, you know you'll get a true-to-life experience.
Let’s say that an operating system needs 120 MB of memory in order to hold all the running programs, but there’s currently only 50 MB of available physical memory stored on the RAM chips. The operating system will then set up 120 MB of virtual memory, and will use a program called the virtual memory manager (VMM) to manage that 120 MB. The VMM will create a file on the hard disk that is 70 MB (120 – 50) in size to account for the extra memory that’s needed. The O.S. will now proceed to address memory as if there were actually 120 MB of real memory stored on the RAM, even though there’s really only 50 MB. So, to the O.S., it now appears as if the full 120 MB actually exists. It is the responsibility of the VMM to deal with the fact that there is only 50 MB of real memory.
- vython September 02, 2013Now, how does the VMM function? As mentioned before, the VMM creates a file on the hard disk that holds the extra memory that is needed by the O.S., which in our case is 70 MB in size. This file is called a paging file (also known as a swap file), and plays an important role in virtual memory. The paging file combined with the RAM accounts for all of the memory. Whenever the O.S. needs a ‘block’ of memory that’s not in the real (RAM) memory, the VMM takes a block from the real memory that hasn’t been used recently, writes it to the paging file, and then reads the block of memory that the O.S. needs from the paging file. The VMM then takes the block of memory from the paging file, and moves it into the real memory – in place of the old block. This process is called swapping and the blocks of memory that are swapped are called pages. The group of pages that currently exist in RAM, and that are dedicated to a specific process, is known as the working set for that process.
credits: programmerinterview(dot)com