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Questions tagged [storage]

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1 answer
43 views

Why is the default page/block size 4 KiB?

Clearly, some empirical study on an older machine helped us choose a 4KiB page size to balance TLB hit rate and fragmentation. Modern hardware and operating systems support this size for backward ...
0 votes
1 answer
395 views

How to calculate number of tuples in a page?

I have been working on this particular question since yesterday and I can seem to figure out how to solve it: Assume that your files are organised based on slotted page array which contains a header (...
0 votes
3 answers
342 views

File conversion to binary format to save storage space

Our test log files are stored in .asc format. Each file contains around 5000 rows of these Logging Strings as shown in the image. I would like to reduce the size of these files.They are around 4-5 MBs ...
0 votes
1 answer
57 views

Memory allocation algorithm over a growing storage

I am going to story data in a growable persistent storage. I need to implement allocation/deallocation (like malloc/free and possibly realloc but in Rust) of continuous regions of memory on this ...
0 votes
0 answers
12 views

How does storage virtualization help?

I am trying to understand various types of virtualization techniques. The concept of Hardware virtualization/Virtual machine was simple enough. However, I am struggling to understand the concept of ...
2 votes
4 answers
7k views

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 ...
3 votes
1 answer
119 views

A data structure for an allocation-free dynamic sample rate buffer

I'm looking for a data structure that would allow storing samples (in O(1)) from a data stream in a fixed-size buffer while the stream length isn't known in advance. Once the buffer size is exhausted ...
0 votes
2 answers
46 views

When a CPU copies instructions from storage into RAM how does it jump to instructions no longer in RAM?

When a CPU needs to get more instructions from storage and copies them to RAM, how does the CPU jump to previous instructions that are no longer in the RAM? Would it have to copy the old instructions ...
0 votes
0 answers
11 views

In SSTables, why is it possible to group records and compress them?

I am currently reading 'Designing Data Intensive Applications' by Kleppman. In the SSTables and LSM Trees section, it is mentioned that one of the advantage of SSTables is: "Since read requests ...
-1 votes
1 answer
79 views

How can you represent 4096 days with 12 bits?

With 12 bits, apparently you can represent $2^{12}$ different days or 11 years. But how? If you have 6 characters YYMMDD and each character represents 8 bits, how can this represent $2^{48}$ days?
-1 votes
2 answers
88 views

What is the minimum number of bytes required to store the sum of two primitive integers?

Motivation An informal way word this question is, How would re-do some of the weird promotion rules in languages descended from C, like C# or Java. The goal would as to minimize human bewilderment ...
0 votes
1 answer
117 views

How can computers tell where the beginning and end of file/packet/frame headers are?

I'd like to know how a computer can determine the beginning and end of certain file components (attributes, headers, frame/packet/segment headers etc.) when these components can be omitted or added in ...
0 votes
1 answer
41 views

Confusion with Hard Disk structure

Studying Os development I encountered the need to interface with the Hard Disk Drive and thus i started learning how it actually works. One of the problems that i found studying was that different ...
2 votes
0 answers
39 views

Primary File Organization in DBMS - Files of ordered records (sorted files)

"Fundamental of Database Systems", 3rd ed. by Elmasri and Navathe, page 136 says: "We can physically order the records of a file on disk based on the values of one of their fields [...]&...
1 vote
1 answer
47 views

Is reading contiguous pages (let's say 4KB) any faster than reading non-contiguous pages on SSDs?

I'm working my way on a problem which requires me to store elements in fixed 4KB-sized pages on an SSD. Each page is requested once for some computation on its elements, and then the CPU requests for ...
1 vote
2 answers
115 views

How can I write 2^65 on my 64-bit computer?

This is possibly a very trivial question for this site. If I have a 64-bit laptop that means 2^64 combinations in total are possible. But I can even get $2^{(x>>>64)}$ on my laptop. Now, it ...
2 votes
1 answer
198 views

Using B+Tree to implement index, when the index-key size and the data-block size are of the same order

I want to implement an Index using a B+Tree as the underlying data structure. The index will have to support key sizes which are of order of my block size, what means I cannot save all the key as a ...
2 votes
2 answers
5k views

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 ...
3 votes
1 answer
72 views

A doubt on best media for a time capsule

So, I have some data to a time capsule project of mine. But the thing is, I need to know the best media on long-time scale to use as storage unity. The time range is 120 years. Now, I've been thinking ...
16 votes
8 answers
6k views

Why we still need Short Term Memory if Long Term Memory can save temporary data?

If RAM is a short term memory and SSD is a long term memory, why don't microarchitecture of computer nowadays use SSD or another long term memory for saving temporary data like hidden variable for ...
1 vote
1 answer
55 views

Why did the concept of "write-protecting" not carry over from floppy disks to USB memsticks and especially external USB HDDs? [closed]

Many times, I've wished to plug in my backup hard disks into my PC without the risk of any of the data being deleted, overwritten, or modified in any manner. Purely for "inspection" and ...
2 votes
1 answer
6k views

SSTF disk scheduling algorithm? What if lowest seek times are equal in either direction?

Using the Shortest-Seek-Time-First (SSTF) disk scheduling algorithm (where we select a request with a minimum seek time from the current head position), what happens if the requests in both directions ...
1 vote
1 answer
44 views

Fair assignment of storage for multiple writers (load balance)

I'm trying to optimize a system with a better algorithm for allocating storage. The system has 'N' writer processes and 'M' disks. (N < 30, M < 10. N can change, M is constant). Any process can ...
0 votes
0 answers
65 views

Does writing more data to disk consume more energy than writing less?

As the title says, I am wondering if writing more data (i.e. larger files) to disk (e.g. Tablet SSDs) will consume more energy than smaller files. My expected answer is "yes, because larger files ...
7 votes
3 answers
863 views

What is the minimum required storage for a sparse, depth-first octree?

For a numerical simulation framework, I use a hierarchical Cartesian grid in 3D to discretize the computational domain. I am thus looking for the most space-efficient way to store the resulting octree ...
5 votes
2 answers
2k views

What course in CS deals with the study of RAM, CPU, Storage?

I watched the Crash Course playlist of Computer Science. It was teaching about RAM, CPU, Storage etc but I felt it was way too fast and only people who have studied the course first hand understood it ...
2 votes
1 answer
67 views

Course teaching time complexities in real life systems

Having mis-read What course in CS deals with the study of RAM, CPU, Storage? I now wonder what course in CS deals with time and space complexities including GPUs, CPU caches in multiple levels, seek ...
1 vote
0 answers
34 views

Does Nand Flash Type Affect the Read Latency Based on Page Content?

In general, we have these types of NAND flash cells: SLC, MLC, TLC, and QLC. Since MLC flash cells can store 2 bits, the content of the cell can be 00, 01, 10, or 11 which are detected using different ...
1 vote
0 answers
22 views

Why do we need volume as an abstraction on top of partition?

I'm curious about what do we need volume as an abstraction on top of hardware partition? What problem it tries to solve? What is the limitation of this concept?
2 votes
0 answers
194 views

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/...
3 votes
4 answers
2k views

time efficient key value store for fast lookup

Let's state a collection of key/values. Key is an unsigned integer (0 - 2^32-1). Hense there are comparable. Value is few bytes fixed size. There are 4M items in the collection. Keys are not evenly ...
0 votes
1 answer
261 views

Most Efficient Way to List All $n$-bit Permutations

Suppose we are tasked with expressing a randomized list of all numbers up to but excluding $2^n$ (ie. a random list of all n-bit numbers). What are some efficient ways to do such a listing using as ...
5 votes
1 answer
2k views

Why does RAID-5 require an additional disk for parity blocks?

I know that RAID-5 consists of block-level striping across multiple disks, but using an additional parity-check block on each disk .. and that at least two disks are required for striping. And it's ...
2 votes
1 answer
572 views

Page cache and its relationship to page table

I was reading about the page cache Page cache - the cache in memory for files, but I couldn't find the answer to my question. Does the page table have anything to do with, or maintain any entries, for ...
0 votes
1 answer
39 views

Creating a numbered list, divided into types, without need for shifting or re-ordering - is this a re-occuring problem

My question is not for a solution to the problem, though I do need to put thought into it but rather my question is if this conceptual problem has a name or has been addressed at already in computer ...
2 votes
1 answer
628 views

What exactly is a "binary file"?

I suspect this may be more of a concept / theory question, but, I haven't been able to wrap my brain around what exactly a binary file is. I've read links such as the below: https://en.wikipedia.org/...
1 vote
0 answers
34 views

How extended logical blocks are mapped to physical device pages?

I'm reading "Decibel: Isolation and Sharing in Disaggregated Rack-Scale Storage" (PDF). On page 6, the author illustrates the concept of "Extended Logical Block"), which is similar to "Data Integrity ...
2 votes
1 answer
1k views

Calculate storage requirements for a data set

I have a simple problem. I can't seem to even find the right search terms to get me pointed in the direction I need to be heading. I'm writing a bunch of integers to disk. Lot's of them. Starting ...
5 votes
1 answer
584 views

Could a standardized ternary system be more efficient than the binary system? [duplicate]

Could a standardized ternary (base-3) system be more efficient than the binary (base-2) system? Binary is efficient for processing using logic gates, but can be bulky when using for file storage or ...
2 votes
0 answers
52 views

Can you read a file as a binary number?

This is a pretty naive question, but I would like to better understand the basics of information storage on a computer. I am not concerned with the detail of how any one operating system achieves ...
3 votes
0 answers
55 views

What data structure should I use for storing my data?

I am currently looking for a way in which I can store my data, and quickly look it up. What currently seem to be the best idea is to use a hash map. reasons: To identify what item I am looking for, ...
0 votes
0 answers
61 views

How are files managed in a filesystem?

I have recently been interested in low level computer science (as a hobby), and I have just learned about the way a computer organizes and stores information on a hard drive. I have learned the basics ...
1 vote
0 answers
624 views

How to calculate multibit trie storage size?

I wish to use a multi-bit trie structure for storing IPv4 forwarding information with a fixed stride width of 8 bits, I think this is also called a "radix of 8" (so for any IP prefix 4 levels will ...
0 votes
1 answer
2k views

How is the data stored in AVL tree in a memory? [duplicate]

I have been struggling to visualize how is the AVL tree is stored in memory? Does it store data in array or list, If so how is it connected with its child and parents.
-1 votes
1 answer
113 views

Comparing the Speed of Random Number Generation to Reading Data

Imagine you need $n$ random numbers from a Gaussian distribution with $\mu=0$ and $\sigma=1$. And you need to use each of these $n$ numbers $k$ times in various operations. Let's identify the numbers ...
0 votes
0 answers
49 views

Should we consider number of surfaces in a disk while calculating effective data transfer rate?

Suppose a disk has Number of surfaces: 8 Number of sectors per track: 20 Sector size: 4000B Number of tracks: 10 It is rotating at 360 rpm. So disk is reading data from one track at an instance....
0 votes
2 answers
413 views

how does a harddisk work? block / sector [closed]

Can someone explain me the way harddisks work? :/ The size of a block is specified in the filesystem, am I right? As you can see in the picture from wikipedia, the disk is divided into circle sectors. ...
1 vote
2 answers
77k views

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

I am having a rather distressing confusion about whether storage media and storage devices are the same terms. I found on this ...
0 votes
2 answers
5k views

1 bit register with data flip flop doesn't store bit?

A 1-bit register: Credit: Elements of Computing Systems by Noam Nisan and Shimon Schocken ISBN-13: 978-0262640688 I know that the data flip flop outputs the input at the previous time step. ...
43 votes
9 answers
13k views

Understanding serialization

I am a software engineer and after a discussion with some colleagues, I realized I do not have a good grasp of the concept serialization. As I understand, serialization is the process of converting ...