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Parallel and Concurrent Programming in Haskell


As one of the developers of the Glasgow Haskell Compiler (GHC) for almost 15 years, I have seen Haskell grow from a niche research language into a rich and thriving ecosystem. I spent a lot of that time working on GHC’s support for parallelism and concurrency. One of the first things I did to GHC in 1997 was to rewrite its runtime system, and a key decision we made at that time was to build concurrency right into the core of the system rather than making it an optional extra or an add-on library. I like to think this decision was founded upon shrewd foresight, but in reality it had as much to do with the fact that we found a way to reduce the overhead of concurrency to near zero (previously it had been on the order of 2%; we’ve always been performance-obsessed). Nevertheless, having concurrency be non-optional meant that it was always a first-class part of the implementation, and I’m sure that this decision was instrumental in bringing about GHC’s solid and lightning-fast concurrency support.

Haskell has a long tradition of being associated with parallelism. To name just a few of the projects, there was the pH variant of Haskell derived from the Id language, which was designed for parallelism, the GUM system for running parallel Haskell programs on multiple machines in a cluster, and the GRiP system: a complete computer architecture designed for running parallel functional programs. All of these happened well before the current multicore revolution, and the problem was that this was the time when Moore’s law was still giving us ever-faster computers. Parallelism was difficult to achieve, and didn’t seem worth the effort when ordinary computers were getting exponentially faster.

Around 2004, we decided to build a parallel implementation of the GHC runtime system for running on shared memory multiprocessors, something that had not been done before. This was just before the multicore revolution. Multiprocessor machines were fairly common, but multicores were still around the corner. Again, I’d like to think the decision to tackle parallelism at this point was enlightened foresight, but

Multifunctional HP Officejet 150 Mobile


Multifunction Devices with Batteries

Via Officejet 150 Mobile, HP (Hewlett-Packard) brings superior features the use of lithium-ion batteries. Even the battery usage on this multifunction device is the first in the world. By using the battery, you can run this device is not currently available grid (PLN). This battery is claimed to last for up to five hundred print document sheet.

u9-435-hp150Meski your physical form, HP still includes a variety of connectivity for easy printing of various devices. You can print directly from the camera using Pictbridge connection, also can print from a memory card slot thanks to the existence of SD and MMC. Any USB port makes HP Officejet 150 Mobile can be used to access and print the content of external media such as flash disks and hard disks. Memory card and flash drive can also be used to store the scanned file. While in the case of the scan function, its use must install the software first included in the package.

In addition, the device also supports printing directly from the smartphone. Unfortunately, given only limited support for Windows Phone and Blackberry platforms. While the operating system is quite popular smartphones such as Android and iOS are not supported. All of which functioned through the touch screen-based fee that is responsive. “Shortage” is in another physical form that are made as short as possible: not supplied buffer to hold the paper. As a result, you will be a little bothered by the scattered papers.

Although the print speed is quite normal, to say the performance is not too slow. Copy and scan process is done using sheet-fed technology. This technology will scan the pages of the paper. When finished scanned per sheet of paper, the results can be printed directly pindaiannya. When PCplus count, nicks exact same time even though the documents are processed differently.

With the innovations presented by HP, you can carry around a print device like a laptop. Thanks to the support of such batteries, as well as direct printing capabilities are fairly a lot, this device is more practical and flexible. If there is a problem with the

How Apollo 11′s 1.024MHz guidance computer did a lot with very little



early 44 years ago computer hardware was in an entirely different place than it is now. The levels of performance don’t even fit on the same scale. The anniversary of the Apollo 11moon landing is upon us, and those brave space pioneers got by without a 3GHz multi-core CPU. The guidance computer used on the Apollo 11 mission ran at only 1.024 MHz.

The moon landing was the height of technological achievement at the time, and some of the rocket technology is still relevant today. That computer, though, has been left in the dust. In fact, it was well and truly obsolete a few years after the landing.

The Intel 8086 came about roughly ten years after the Apollo landing, marking the beginning of x86. Apollo 11’s computer had 4 registers — essentially slots for holding numeric values. The 8086 boosted that to eight 16-bit registers.

The IBM PC XT ran the next version of that chip, the famous 8088. This computer ran at 4.077MHz, which sounds incredibly slow by today’s standards, but is still four times faster than the Apollo 11computer. The XT also packed in eight times the memory used on Apollo 11.

The Apollo 11 guidance computer actually had some impressive software features for a system that didn’t even run a graphical interface. It could multitask up to 8 different operations, but it didn’t work the way we think of multitasking. Today’s operations use preemptive multitasking that allows the OS to distribute computing resources as needed. On Apollo 11, programs were in charge and had to give control back to the OS periodically. A kind of virtual machine was used to allow developers to mix hardware-level instructions with virtual machine commands within the same assembler code.

Inputting commands required translating the English words into “verb noun pairs,” which could be input as numbers. There was a handy sign in the cabin as a reminder. To top it all off, none of the computer’s systems were software upgradeable. All the code was stored in read-only memory. Several years after Apollo 11, Apollo 14 was forced to manually input the code to patch a system malfunction — it took

NSA intercepted, Apple, Google, Microsoft alliance

computer people

Jakarta – A giant technology company formed an alliance to demand transparency from the U.S. government related information monitoring program of the National Security Agency (NSA) called PRISM.
The alliance involves companies such as Apple, Google, Facebook, and Microsoft. In alliance was also a number of civic groups. In a letter that will be announced in a few hours, the alliance which amounts to 63 companies, investors, and non-profit organizations is asking for clearer rules about such things.
“Basic information about the way the government enforce laws related activities have been published during this investigation does not interfere with the investigation,” read one of the points in the letter obtained by AllThingsD on Wednesday, July 17, 2013.
The Alliance requested that they be allowed the right to announce the number of government requests for data on the users of their services. They also requested that the number of users, accounts, and information held gadget that can be announced.
Alliance also assess the amount of requests basic information about the content and the user, could be made public as part of their transparency.
At the same time, the alliance will also ask the government to announce a number of requests and the number of individuals whose data is requested from the technology companies.
This letter will be addressed to President Barack Obama and congressional leaders. Here are some names of firms and associations involved in this alliance:
Yahoo, AOL, Apple, Digg, Dropbox, Evoca, Facebook, Google, HeyZap, LinkedIn, Meetup, Microsoft, Mozilla, Reddit,, Tumblr, and Twitter.
Also there younow, Union Square Ventures, Y Combinator, New Atlantic Ventures, The Electronic Frontier Foundation, Human Rights Watch, the American Civil Liberties Union, the Center for Democracy & Technology.
In addition, there are elements of the press and advocacy organizations such as Reporters Committee for Freedom of the Press, Public Knowledge, the Computer & Communications Industry Association, Reporters Without Borders, and the Wikimedia Foundation.

Samsung Galaxy S4 Software Will Increase

Computer Monitors Shaking Hands

Kansas – Some telecommunications companies in the United States, such as Verizon, AT & T and Sprint are currently in the process of major reform efforts on a smart phone that is now being loved, Samsung Galaxy S4. Although there is no official announcement from them, any reports from various sources stating the same thing.
According to a report quoted by CNET site, with updates on Samsung Galaxy S4 users can move apps from internal storage to microSD card. This capability can empty the internal storage. So that the performance can be optimized.
Other updates to security software yitu Samsung Knox and bootloader. Developmental changes are also located in the settings are easy to apply and other additional software.
Users of Samsung Galaxy S4, just need to wait for an official announcement about this renewal. Sprint and AT & T amid spreading rumors this renewal. While Verizon is working on desktop software via Samsung Kies.