Bandwidth Compression, Expand Networks takes application traffic management to the next level by reducing WAN costs and improving application performance. Expand Network’s Accelerators and ExpandView product lines are a class apart from other WAN optimization and traffic management solutions. In addition to bandwidth expansion capabilities, the Accelerators provide a rich set of features that improve application response times and provide layer 7 visibility and control tools that enable network managers to align network resources with business priorities.

This unique combination of features is achieved through next-generation WAN compression, application-specific acceleration, Layer 7 QoS capabilities and sophisticated monitoring and reporting. Nowhere else will you find such an intelligent WAN optimization device. Accelerators are available for IP or serial traffic and can support enterprise needs for accelerating encrypted traffic. They can support mesh networks and can be deployed On-Path between the LAN segment and router, On-LAN by connecting an Accelerator non-obtrusively to a switch or router or Serial on the interface between the router and the CSU/DSU.

ExpandView is Expand Networks Application Traffic Management System. ExpandView automatically discovers and classifies 100+ enterprise applications while detecting WAN performance problems and proactively fixing them for optimal application delivery. With robust centralized configuration and management ExpandView is ideal for large scale deployments of Accelerators

Advantages

Increase average WAN capacity by 100-400%+

Peaks of 1000%+

IP and non-IP applications

Why Expand Networks?

Unbeatable ROI

Standards-based architecture

Acceleration performance and scalability

Complete solution

Dominant market leader

Many different forms of storage, based on various natural phenomena, have been invented. So far, no practical universal storage medium exists, and all forms of storage have some drawbacks. Therefore a computer system usually contains several kinds of storage, each with an individual purpose.

A digital computer represents data using the binary numeral system. Text, numbers, pictures, audio, and nearly any other form of information can be converted into a string of bits, or binary digits, each of which has a value of 1 or 0. The most common unit of storage is the byte, equal to 8 bits. A piece of information can be handled by any computer whose storage space is large enough to accommodate the binary representation of the piece of information, or simply data. For example, using eight million bits, or about one megabyte, a typical computer could store a short novel.

Traditionally the most important part of every computer is the central processing unit (CPU, or simply a processor), because it actually operates on data, performs any calculations, and controls all the other components.

Without a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output the result. It would have to be reconfigured to change its behavior. This is acceptable for devices such as desk calculators or simple digital signal processors. Von Neumann machines differ in that they have a memory in which they store their operating instructions and data. Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can simply be reprogrammed with new in-memory instructions; they also tend to be simpler to design, in that a relatively simple processor may keep state between successive computations to build up complex procedural results. Most modern computers are von Neumann machines.

In practice, almost all computers use a variety of memory types, organized in a storage hierarchy around the CPU, as a trade-off between performance and cost. Generally, the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its access latency is from the CPU. This traditional division of storage to primary, secondary, tertiary and off-line storage is also guided by cost per bit.

Hierarchy of storage

Various forms of storage, divided according to their distance from the central processing unit. The fundamental components of a general-purpose computer are arithmetic and logic unit, control circuitry, storage space, and input/output devices. Technology and capacity as in common home computers around 2005.

Primary storage

Direct links to this section: Primary storage, Main memory, Internal Memory.

Primary storage (or main memory or internal memory), often referred to simply as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in uniform manner.

Historically, early computers used delay lines, Williams tubes, or rotating magnetic drums as primary storage. By 1954, those unreliable methods were mostly replaced by magnetic core memory, which was still rather cumbersome. Undoubtedly, a revolution was started with the invention of a transistor, that soon enabled then-unbelievable miniaturization of electronic memory via solid-state silicon chip technology.

This led to a modern random-access memory (RAM). It is small-sized, light, but quite expensive at the same time. (The particular types of RAM used for primary storage are also volatile, i.e. they lose the information when not powered).

As shown in the diagram, traditionally there are two more sub-layers of the primary storage, besides main large-capacity RAM:

• Processor registers are located inside the processor. Each register typically holds a word of data (often 32 or 64 bits). CPU instructions instruct the arithmetic and logic unit to perform various calculations or other operations on this data (or with the help of it). Registers are technically among the fastest of all forms of computer data storage.
• Processor cache is an intermediate stage between ultra-fast registers and much slower main memory. It’s introduced solely to increase performance of the computer. Most actively used information in the main memory is just duplicated in the cache memory, which is faster, but of much lesser capacity. On the other hand it is much slower, but much larger than processor registers. Multi-level hierarchical cache setup is also commonly used—primary cache being smallest, fastest and located inside the processor; secondary cache being somewhat larger and slower.

Main memory is directly or indirectly connected to the CPU via a memory bus. It is actually two buses (not on the diagram): an address bus and a data bus. The CPU firstly sends a number through an address bus, a number called memory address, that indicates the desired location of data. Then it reads or writes the data itself using the data bus. Additionally, a memory management unit (MMU) is a small device between CPU and RAM recalculating the actual memory address, for example to provide an abstraction of virtual memory or other tasks.

As the RAM types used for primary storage are volatile (cleared at start up), a computer containing only such storage would not have a source to read instructions from, in order to start the computer. Hence, non-volatile primary storage containing a small startup program (BIOS) is used to bootstrap the computer, that is, to read a larger program from non-volatile secondary storage to RAM and start to execute it. A non-volatile technology used for this purpose is called ROM, for read-only memory (the terminology may be somewhat confusing as most ROM types are also capable of random access).

Many types of “ROM” are not literally read only, as updates are possible; however it is slow and memory must be erased in large portions before it can be re-written. Some embedded systems run programs directly from ROM (or similar), because such programs are rarely changed. Standard computers do not store non-rudimentary programs in ROM, rather use large capacities of secondary storage, which is non-volatile as well, and not as costly.

Recently, primary storage and secondary storage in some uses refer to what was historically called, respectively, secondary storage and tertiary storage.^[1]

Secondary storage

Secondary storage (or external memory) differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage. Secondary storage does not lose the data when the device is powered down—it is non-volatile. Per unit, it is typically also an order of magnitude less expensive than primary storage. Consequently, modern computer systems typically have an order of magnitude more secondary storage than primary storage and data is kept for a longer time there.

In modern computers, hard disk drives are usually used as secondary storage. The time taken to access a given byte of information stored on a hard disk is typically a few thousandths of a second, or milliseconds. By contrast, the time taken to access a given byte of information stored in random access memory is measured in billionths of a second, or nanoseconds. This illustrates the very significant access-time difference which distinguishes solid-state memory from rotating magnetic storage devices: hard disks are typically about a million times slower than memory. Rotating optical storage devices, such as CD and DVD drives, have even longer access times. With disk drives, once the disk read/write head reaches the proper placement and the data of interest rotates under it, subsequent data on the track are very fast to access. As a result, in order to hide the initial seek time and rotational latency, data are transferred to and from disks in large contiguous blocks.

When data reside on disk, block access to hide latency offers a ray of hope in designing efficient external memory algorithms. Sequential or block access on disks is orders of magnitude faster than random access, and many sophisticated paradigms have been developed to design efficient algorithms based upon sequential and block access . Another way to reduce the I/O bottleneck is to use multiple disks in parallel in order to increase the bandwidth between primary and secondary memory.^[2]

Some other examples of secondary storage technologies are: flash memory (e.g. USB flash drives or keys), floppy disks, magnetic tape, paper tape, punched cards, standalone RAM disks, and Iomega Zip drives.

The secondary storage is often formatted according to a file system format, which provides the abstraction necessary to organize data into files and directories, providing also additional information (called metadata) describing the owner of a certain file, the access time, the access permissions, and other information.

Most computer operating systems use the concept of virtual memory, allowing utilization of more primary storage capacity than is physically available in the system. As the primary memory fills up, the system moves the least-used chunks (pages) to secondary storage devices (to a swap file or page file), retrieving them later when they are needed. As more of these retrievals from slower secondary storage are necessary, the more the overall system performance is degraded.

Tertiary storage

Tertiary storage or tertiary memory,^[3] provides a third level of storage. Typically it involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device according to the system’s demands; this data is often copied to secondary storage before use. It is primarily used for archival of rarely accessed information since it is much slower than secondary storage (e.g. 5–60 seconds vs. 1-10 milliseconds). This is primarily useful for extraordinarily large data stores, accessed without human operators. Typical examples include tape libraries and optical jukeboxes.

When a computer needs to read information from the tertiary storage, it will first consult a catalog database to determine which tape or disc contains the information. Next, the computer will instruct a robotic arm to fetch the medium and place it in a drive. When the computer has finished reading the information, the robotic arm will return the medium to its place in the library.

Off-line storage

Off-line storage is a computer data storage on a medium or a device that is not under the control of a processing unit.^[4] The medium is recorded, usually in a secondary or tertiary storage device, and then physically removed or disconnected. It must be inserted or connected by a human operator before a computer can access it again. Unlike tertiary storage, it cannot be accessed without human interaction.

Off-line storage is used to transfer information, since the detached medium can be easily physically transported. Additionally, in case a disaster, for example a fire, destroys the original data, a medium in a remote location will probably be unaffected, enabling disaster recovery. Off-line storage increases general information security, since it is physically inaccessible from a computer, and data confidentiality or integrity cannot be affected by computer-based attack techniques. Also, if the information stored for archival purposes is accessed seldom or never, off-line storage is less expensive than tertiary storage.

In modern personal computers, most secondary and tertiary storage media are also used for off-line storage. Optical discs and flash memory devices are most popular, and to much lesser extent removable hard disk drives. In enterprise uses, magnetic tape is predominant. Older examples are floppy disks, Zip disks, or punched cards.

Characteristics of storage

Volatility

Non-volatile memory

Will retain the stored information even if it is not constantly supplied with electric power. It is suitable for long-term storage of information. Nowadays used for most of secondary, tertiary, and off-line storage. In 1950s and 1960s, it was also used for primary storage, in the form of magnetic core memory.

Volatile memory

Requires constant power to maintain the stored information. The fastest memory technologies of today are volatile ones (not a universal rule). Since primary storage is required to be very fast, it predominantly uses volatile memory.

Differentiation

Dynamic random access memory

A form of volatile memory which also requires the stored information to be periodically re-read and re-written, or refreshed, otherwise it would vanish.

Static memory

A form of volatile memory similar to DRAM with the exception that it never needs to be refreshed.

Mutability

Read/write storage or mutable storage

Allows information to be overwritten at any time. A computer without some amount of read/write storage for primary storage purposes would be useless for many tasks. Modern computers typically use read/write storage also for secondary storage.

Read only storage

Retains the information stored at the time of manufacture, and write once storage (Write Once Read Many) allows the information to be written only once at some point after manufacture. These are called immutable storage. Immutable storage is used for tertiary and off-line storage. Examples include CD-ROM and CD-R.

Slow write, fast read storage

Read/write storage which allows information to be overwritten multiple times, but with the write operation being much slower than the read operation. Examples include CD-RW and flash memory.

Accessibility

Random access

Any location in storage can be accessed at any moment in approximately the same amount of time. Such characteristic is well suited for primary and secondary storage.

Sequential access

The accessing of pieces of information will be in a serial order, one after the other; therefore the time to access a particular piece of information depends upon which piece of information was last accessed. Such characteristic is typical of off-line storage.

Addressability

Location-addressable

Each individually accessible unit of information in storage is selected with its numerical memory address. In modern computers, location-addressable storage usually limits to primary storage, accessed internally by computer programs, since location-addressability is very efficient, but burdensome for humans.

File addressable

Information is divided into files of variable length, and a particular file is selected with human-readable directory and file names. The underlying device is still location-addressable, but the operating system of a computer provides the file system abstraction to make the operation more understandable. In modern computers, secondary, tertiary and off-line storage use file systems.

Content-addressable

Each individually accessible unit of information is selected based on the basis of (part of) the contents stored there. Content-addressable storage can be implemented using software (computer program) or hardware (computer device), with hardware being faster but more expensive option. Hardware content addressable memory is often used in a computer’s CPU cache.

Capacity

Raw capacity

The total amount of stored information that a storage device or medium can hold. It is expressed as a quantity of bits or bytes (e.g. 10.4 megabytes).

Memory storage density

The compactness of stored information. It is the storage capacity of a medium divided with a unit of length, area or volume (e.g. 1.2 megabytes per square inch).

Performance

Latency

The time it takes to access a particular location in storage. The relevant unit of measurement is typically nanosecond for primary storage, millisecond for secondary storage, and second for tertiary storage. It may make sense to separate read latency and write latency, and in case of sequential access storage, minimum, maximum and average latency.

Throughput

The rate at which information can be read from or written to the storage. In computer data storage, throughput is usually expressed in terms of megabytes per second or MB/s, though bit rate may also be used. As with latency, read rate and write rate may need to be differentiated. Also accessing media sequentially, as opposed to randomly, typically yields maximum throughput.

Environmental Impact

The impact of a storage device on the environment.

Energy

• Energy Star certified power adapters for storage devices reduce power consumption 30 percent on average^[5]
• Storage devices that reduce fan usage, automatically shut-down during inactivity, and low power hard drives can reduce energy consumption 90 percent. ^[6]
• 2.5 inch hard disk drives often consume less power than larger ones.^[7][8] Low capacity solid-state drives have no moving parts and consume less power than hard disks.^[9][10][11] Also, memory may use more power than hard disks.^[11]

Recycling

• Some devices are made of recyclable materials like aluminum, bamboo, or plastics
• Easily disassembled devices are easier to recycle if only certain parts are recyclable
• Packaging may be recyclable and some companies print instructions on the box or use recyclable paper for the instructions instead of waxed paper

Manufacturing

• The amount of raw materials (metals, aluminum, plastics, lead) used to manufacture the device
• Excess waste materials and if they are recycled
• Chemicals used in manufacturing
• Shipping distance for the device itself and parts
• Amount of packaging materials and if they are recyclable

References

Wikimedia Commons has media related to: Computer memory

This article incorporates public domain material from the General Services Administration document “Federal Standard 1037C”.

Computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.

In contemporary usage, memory usually refers to a form of semiconductor storage known as random-access memory (RAM) and sometimes other forms of fast but temporary storage. Similarly, storage today more commonly refers to mass storage — optical discs, forms of magnetic storage like hard disk drives, and other types slower than RAM, but of a more permanent nature. Historically, memory and storage were respectively called main memory and secondary storage. The terms internal memory and external memory are also used.

The contemporary distinctions are helpful, because they are also fundamental to the architecture of computers in general. The distinctions also reflect an important and significant technical difference between memory and mass storage devices, which has been blurred by the historical usage of the term storage. Nevertheless, this article uses the traditional nomenclature.

Wajahnya lugu. Sederhana. Tutur katanya simpatik. ”Soal gaji sih terserah saja. Saya terima. Yang penting bisa kerja membantu Tuan dan Nyonya,” ujar Yati. Sang majikan terkesan. Yati diterima menjadi pembantu rumah tangga. Ia dipercaya. Kunci-kunci rumah dipegangnya. Dua bulan kemudian, majikannya sangat kaget ketika tiba di rumah. Semua barang berharga mereka habis terkuras. Yati lenyap. Rupanya ia adalah anggota sindikat perampok yang beraksi dengan bepura-pura menjadi pembantu. Wajahnya tulus, namun hatinya bulus!

Sulit mencari orang berhati tulus. Langka, tetapi sangat berharga. Waktu mencari pengganti Yudas, para murid tidak mencari orang hebat. Belajar dari pengkhianatan Yudas, mereka sadar bahwa faktor terpenting yang harus ada dalam diri seorang murid adalah ketulusan hati. Namun siapa yang bisa mengenal isi hati? Tuhan! Mereka pun lantas berdoa: “Ya Tuhan, Engkaulah yang mengenal hati semua orang, tunjukkanlah kiranya siapa yang Engkau pilih” (ayat 24). Soal hati itu perkara penting. Percuma menjadi orang berprestasi apabila tanpa ketulusan hati. Akhirnya, Tuhan memilih Matias, tokoh yang tidak terkenal. Namanya tak pernah muncul dalam kitab Injil maupun surat Rasuli. Ia bekerja dibalik layar. Namun, ketulusan hatinya membuat Tuhan berkenan.

Orang yang tulus hati membuat rencana tanpa intrik. Berbicara tanpa melebih-lebihkan. Memberi bantuan tanpa pamrih. Menampilkan diri apa adanya tanpa berusaha terlihat suci. Ia benci kemunafikan dan kepalsuan. Seperti itukah Anda? Apakah Anda dikenal sebagai orang yang tulus hati?

Ku tak dapat lupakan

kebaikan yang kutrima

pengorbanan-Mu yang mulia

jadikanku berharga

Kau tulus menerima

aku apa adanya

kekuatan kasih-Mu nyata

memulihkan hidupku

Kau bukan Tuhan yang melihat rupa

Kau bukan Tuhan yang memandang harta

hati hamba yang s’lalu Kau cari

biar Kau temukan di dalamku

S’lamaku hidup ku mau menyembah-Mu

s’bab Engkau sangat berarti bagiku

yang terbaik yang ada padaku

kupersembahkan kepada-Mu

Yesusku

Tak terbayang hidupku tanpamu

tak ternilai kasih-Mu padaku

dan mulutku s’lalu menyembah-Mu

Gunung bersorak

laut bergelora

lutut bertelut

lidah pun mengaku

dan hidupku s’lalu menyembah-Mu

How I love You

How I love You

is how I love You

hanya Kau Yesus

Sering kali kudatang Tuhan

hanya karena sejuta keluhan

Sering kali kulupa Tuhan

seharusnya kudatang

dengan segenap rindu

dari lubuk hatiku

dengan hasrat yang tulus

karna kucinta pada-Mu

tak hanya memikirkan

berkat yang Kau berikan

sungguh hanya karna kumengasihi-Mu Yesus

Sering kali aku berdoa

hanya karna tak ingin dicela

namun kini kusadar Tuhan

seharusnya kudatang

dengan segenap rindu

dari lubuk hatiku

dengan hasrat yang tulus

karna kucinta pada-Mu

tak hanya memikirkan

berkat yang Kau berikan

sungguh hanya karna kumengasihi-Mu Yesus

]]> http://kecoasalto.wordpress.com/2010/02/07/seharusnya-kudatang/feed/ 1 kecoasalto http://kecoasalto.wordpress.com/2010/02/03/hrp-4c-robot-cantik-dari-jepang/ http://kecoasalto.wordpress.com/2010/02/03/hrp-4c-robot-cantik-dari-jepang/#comments Wed, 03 Feb 2010 16:48:26 +0000 kecoasalto http://kecoasalto.wordpress.com/?p=32 ]]> Hiroshi Hirukawa, salah satu ilmuwan dari National Institute of Advanced Industrial Sciences and Technology dari Jepang,  Robot terbaru buatan Jepang ini tidak hanya cantik, tetapi juga bisa berlenggak-lenggok dengan pinggul bergoyang saat berjalan. “Secara teknologi, ia sudah mencapai level tersebut,” ujar Hiroshi Hirukawa

HRP-4C,  telah memasuki level gerakan-gerakan seperti manusia. Ekspresi wajah juga dapat berubah-ubah dari sedih ke senang dengan mengatur gerakan mata dan mulut sesuai perintah.  HRP-4C ini di ciptakan untuk menjadi  pemandu atau instruktur. Misalnya, pemandu arah di taman kota atau sekadar menggerak-gerakkan badan untuk memberi hiburan pengunjung tempat hiburan.

Namun Sayang HRP-4C ini terbilang sangat mahal dengan harga 20 juta yen atau sekitar Rp 2,4 miliar. Meski demikian, software yang mengatur gerakan robot tersebut akan disumbangkan kepada publik.

sumber : kompas

Ini adalah bahan renungan untuk hari ini, diambil dari Renungan Pagi. Bacaan alkitab lengkapnya dari Pengkhotbah 3 : 1-6 dengan perikop “Untuk segala sesuatu ada waktunya”.

Firman Tuhan pada hari ini sungguh sangat luar biasa buat saya pribadi khususnya. Terima kasih Tuhan Yesus untuk segala sesuatunya. Karena ku tahu Tuhanku bekerja untuk mendatangkan kebaikan walaupun sering kali yang terjadi tak seperti yang ku ingini. Tapi yang ku tahu pasti kasih Allahku tak kan berhenti ^^

Alkitab mengungkapkan sebuah cara yang sangat berbeda dengan dunia. Untuk menghadapi musuh, kita tidak perlu buru-buru menggunakan senjata atau kepalan tangan, tetapi dengan kasih. Sebaliknya, anak-anak Tuhan membalas orang yang mencaci dan menganiaya mereka bukan dengan kekerasan atau kebencian, melainkan dengan doa. Inilah prinsip anak-anak Allah. Jikalau kita bersikap dan berbuat baik hanya kepada orang yang juga berlaku baik kepada kita, lalu apa bedanya anak Allah dengan orang yang tidak mengenal Allah (ayat 46,47)?

Untuk mempraktikkan perintah ini memang tidak mudah. Namun, jika kita mengaku sebagai anak-anak Allah, kita harus melakukannya. Mari kita mulai dengan langkah-langkah kecil. Berdoalah untuk musuh kita, lalu lakukan hal yang sederhana untuknya. Dalam hal ini Matthew Henry, seorang hamba Tuhan pada abad ke-16, mengusulkan agar kita belajar untuk membalas cercaan bukan dengan cercaan, melainkan dengan kata-kata yang sopan dan lemah lembut.

KASIH SEJATI AKAN TERUJI DI SAAT SULIT, SEPERTI KETIKA MENGHADAPI MUSUH YANG MEMBAWA SAKIT