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SEARCH KEYWORD -- Disk

  Implementation of Tower of Hanoi

The Tower of Hanoi is a mathematical game or puzzle. It consists of three rods, and a number of disks of different sizes which can slide onto any rod. The puzzle starts with the disks in a neat stack in ascending order of size on one rod, the smallest at the top, thus making a conical shape. The objective of the puzzle is to move the entire stack to another rod, obeying the following rules: Only one disk may be moved at a time. Each move consists of taking the upper disk fro...

   Algorithm,Tower of Hanoi     2012-08-20 02:15:55

  How Kafka achieves high throughput low latency

Kafka is a message streaming system with high throughput and low latency. It is widely adopted in lots of big companies. A well configured Kafka cluster can achieve super high throughput with millions of concurrent writes. How Kafka can achieve this? This post will try to explain some technologies used by Kafka. Page cache + Disk sequential write Every time when Kafka receives a record, it will write it to disk file eventually. But if it writes to disk every time it receives a record, it would ...

   BIG DATA,KAFKA     2019-03-08 09:42:57

  Full disk encryption is too good, says US intelligence agency

You might be shocked to learn this, but when a quivering-lipped Chloe from 24 cracks the encryption on a terrorist’s hard drive in 30 seconds, the TV show is faking it. “So what? It’s just a TV show.” Well, yes, but it turns out that real federal intelligence agencies, like the FBI, CIA, and NSA, also have a problem cracking encrypted hard disks — and according to a new research paper, this is a serious risk to national security.The study...

   FDE,Full disk encryption,Crack,Difficulty     2011-11-19 01:55:17

  RAM is the new disk...

Jim Gray, a man who has contributed greatly to technology over the past 40 years, is credited with saying that memory is the new disk and disk is the new tape. With the proliferation of "real-time" web applications and systems that require massive scalability, how are hardware and software relating to this meme? Tim Bray, in his discussions about grid computing before it became such a hot topic, pointed out how advances in hardware around RAM and networking were allowing for the creation...

   RAM,Flash,Memory,,Future,Disk     2011-08-12 07:34:27

  Unix directory hierarchy history

As a beginner user of Unix or Linux, people would frequently get confused about the use of different directories of the system.  For example, there is a /bin directory under root(/), it is used to store binary files. However, there are /usr/bin and /usr/local/bin under /usr which are used for storing binary files as well. Some systems even have /opt/bin. What are the differences among them? Though there are articles explaining different directories in *nix such as Filesystem Hierarchy Stan...

   UNIX,LINUX,FILESSYTEM,DIRECTORY HIERARCHY,HISTORY     2016-10-21 23:47:17

  Fujitsu CTO: Flash is just a stopgap

Flash is a necessary waystation as we travel to a single in-memory storage architecture. That's the view from a Fujitsu chief technology officer's office. Dr Joseph Reger, CTO at Fujitsu Technology Solutions, is that office-holder, and – according to him – flash is beset with problems that will become unsolvable. He says we are seeing increases in flash density at the expense of our ability to read and write data. Each shrink in process geometry, from 3X to 2X and onto 1X, ...

   Flash,Memory,Bottleneck,Limitation,Futur     2011-08-12 07:31:34

  How to forcibly eject a CD/DVD from a MacBook Air USB SuperDrive

So you've got a DVD stuck in the external USB SuperDrive that connects to the MacBook Air? And you've tried hitting the magic Eject button on the keyboard to no avail?And you've tried drutil tray eject at the command-line? And you've tried booting with Option held down and clicking eject? And you've tried plugging the drive into other machines (Macs, Windows PCs, Linux machines) to no avail?What do you do?Clearly you hit the physical eject button, right? Every DVD drive has one of those. On the ...

   Apple,Macbook,USB Drive,Ejection     2011-11-17 08:39:56

  How does computer boot up?

The whole boot process of computer can be summarized in 4 phases. 1. BIOS In the 70's  read-only memory(ROM) was invented. The boot program is written into ROM, the first thing the computer does is to read and execute this program when it's powered on. The program in this chip is called "Basic Input/Output System" (BIOS). 1.1 Power-On Self-Test The BIOS will first check whether the computer hardware can fulfill the basic conditions for booting up, this process is called Power-On Self-Test...

   Computer, boot, partition     2013-02-23 23:19:47

  Chrome to block mixed content downloads in version 86

Google has announced its plan to block mixed content downloads in Chrome in February 2020 and now the day to block mixed content downloads is coming soon as we are nearing October when Chrome 86 is supposed to be released. What is mixed content downloads? According to Google, it is non-HTTPS downloads started on secure pages. For example, if you access a page called https://example.com/download, and in this page, there is a download link to http://download.example.com/something, ...

   CHROME,MIXED CONTENT DOWNLOADS     2020-09-18 21:10:53

  What are some lesser known but useful Unix commands?

A few that come to mind, some less known, some more: xargs or parallel: run things in parallel, with lots of options sed and awk: more well-known but still super useful for processing text files, and faster than Python or Ruby m4: simple macro processor screen: powerful terminal multiplexing and session persistence yes: print a string a lot cal: nice calendar env: run a command (useful in scripts) look: find English words (or lines in a file) beginning with a string cut and paste and join: data...

   Linux,Unix,Command,Less used     2011-12-27 09:27:49

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