Stac did not invent data compression, which dates to the 1940s. Stac, in an effort led by attorney morgan chu, sued microsoft for infringement of two of its data compression patents, and won. It was later specified as a compression algorithm for various network protocols. Is a compression company like pied piper ever feasible in. Stac software tape turbo with error recovery sources. It has been a busy few months for stac electronics inc, the carlsbad, californiabased data compression company. Each stac test harness embodies the industrys best practices in four areas.
The company builds on these advancements to create highperformance systems recovery software solutions to protect businesscritical data. It is known primarily for its lempelziv stac lossless compression algorithm and stacker disk compression utility for compressing data for storage. If the drive does not feature data compression the data is backed up uncompressed. The size of the award was based on estimated royalties for stac s data compression program. While trying to see if stac ever went into the disk compression busness again, i ran across this interesting bit of software, dmsdos, which is a kernel module for versions 2. Hi all, how to determine if software compression really help to transport more data over a serial link. Hello i have enabled stac compression on hdlc serial link. A stac pack is software that enables a given stac test harness to conduct tests of a specific product depending on the benchmark, this might be a particular database, a particular processor, etc. Stac electronics, originally incorporated as state of the art consulting and later shortened to stac, inc. Is a compression company like pied piper ever feasible in the. I choose 8192 bytes icmp to test the compression and got below results. Stac compression is capable of compressing data by a factor of about four explanation of stac compression. That paper was a byproduct of an initiative in the stac big data sig to develop technologyagnostic benchmarks based on big data workloads.
With ondemand access to safety, training, and certifications via the stac card or stac sticker instant. Aug 14, 2018 software engineers have always developed new ways of fitting a lot of data into a small space. The backup exec includes two data compression types. Software based exar lempleziv stac lossless data compression and decompression algorithms. Uses stac software data compression, which compresses the data before it is sent to the storage device. Stac software and peregrine systems team up to integrate products stac claims that the concept was developed by them and licensed to hp for use on its servers and dat8 and dat24 drives. In hindsight, it wouldve been much better for them to buy stac outright, but i guess they decided to go the less noble route of software piracy. It is known primarily for its lempelzivstac lossless compression algorithm and stacker disk compression utility for compressing data for storage. This document describes the use of the stac lzs data compression algorithm, with single or multiple compression histories, for compressing ppp encapsulated packets. District court found that the datacompression technology contained in microsofts msdos 6. Fiala and greene obtained in 1990 a patent 4,906,991 on all implementations of lz77 using a tree data structure.
There are compression methods for data entire files, links data that travels between routers, hard drives data stored on a hard drive, and so on. It enables reducing the storage size of one or more data instances or elements. Stac also implements a simple zero cost rle compression. Lempelzivstac lzs, or stac compression is a lossless data compression algorithm that uses a combination of the lz77 slidingwindow compression algorithm and fixed huffman coding. Cisco 700 series isdn access routers cisco 700 series integrated services digital network isdn. Without data compression a 3 minute song would be over 100mb and a 10 minute video would easily be over 1gb.
Microsoft settles patent dispute with stac, agrees to. Configuring compression on a serial interface with a command such as compress stac automatically enables hardware compression if it is available. An explanation of hardware and software compression used with backup exec how does compression work. Benefits when you own a cisco 700 series access router, you have a. Few areas cry out for good technology benchmarks more than the wild west of big data. I run it three times and got three different compression ratio. Stacker would create a file on your disk, then present that file as a virtual disk that your programs could run. The doublecard also lets you compress your 95lxs c drive. Data compression internet ready ip 30 yes remote of. Stac compression is capable of compressing data by a factor of about four. The sacomp1 and sacomp4 data compression service adapters csas are available on cisco 7200 series routers, on secondgeneration versatile interface processors vip2s in cisco 7500 series routers, and on cisco 7000 series routers with the 7000 series route switch processor rsp7000 and 7000 series chassis interface rsp7000ci. It was originally developed by stac electronics for tape compression, and subsequently adapted for hard disk compression and sold as the stacker disk compression software. Jan 15, 2008 data compression reduces the size of data frames to be transmitted over a network link.
The doublespace data compression system, which comes free with. Microsoft settles patent dispute with stac, agrees to license. Gzip is the default compression scheme, but you can use an additional setting to change the compression scheme on a client. This option uses hardware data compression if the storage device supports it. Stac big data sig stac insight for the algorithmic. Data compression is also known as source coding or bitrate reduction. Lossless data compression is used ubiquitously in computing, from saving space on your personal computer to sending data over the web, communicating over a secure shell, or viewing a png or. May 28, 2019 data compression is the process of modifying, encoding or converting the bits structure of data in such a way that it consumes less space on disk. For compression, a scope needs to be set ahead of time. The stac6 series stepper drives are powerful, twophase, bipolar step motor drives for highspeed, hightorque applications. This type solely uses the nt hardware compression technology.
And this was certainly the case to some degree, with the quarter inch committee a group focused on the uptake of quarterinchwide computer tape drives implementing stac s research into its qic122 data compression standard. Mar 06, 1994 stac did not invent data compression, which dates to the 1940s. Software compression is available for all storage media. A stac test harness is software that enables the execution of stac benchmarks. Jan 09, 2009 there are 2 data compression types in backup exec. Software compression compresses the data either before it is sent from a remote system if backing up using a remote agent, or before being sent to the tape drive if backing up a local host server system. A data compression technique from stac, used with modems.
Backup exec compression types deciphering lifes source code. You can use the compress stac software command to force the use of software compression. Stac was introduced data compression software which allowed pc users to double their hard drive capacity microsoft was launching an upgrade to its operating system and was searching for a selling feature. For auxiliary copy operations, data is copied in the compressed state. General options for backup jobs and templates symantec. File compression plays a big part in connecting us, letting us send less data down the line so we can have faster downloads and fit more connections onto busy networks. Hence, if the compression is performed using any version of backup exec, there. I have 2 sites connected via 64kbps serial link routers 3620 running ios 12. A year later, the party who was seeking to license the property suddenly is in the market with a similar, if not identical, product and the outraged owner leaps into. The stac training tracking software provides accountability, reliability and verification in matters relating to safety, training, and certifications.
Lossless data compression is the size reduction of a file, such that a decompression function can restore the original file exactly with no loss of data. Stac is listed in the worlds largest and most authoritative dictionary database of abbreviations and acronyms the free dictionary. Stacker file compression software and the ace doublecard 2. Previo, hp roll out network appliance computerworld. Lucent technologies model number comcode description price pipeline 15 isdn bri products p751sbriasa 408046035 pipeline 75 with ipipxappletalk routing, stac 4. Mp3, mp4, rar, zip, jpg and png files along with many others all use compressed data.
Hence, if the compression is performed using any version of backup exec, there will be no issues while restoring the same data. If the drive does not feature data compression, the data is. Hardware compression option 1 backs up the data uncompressed then runs an nt compression program on the data whilst on the backup media. This slide is subject to the proprietary restrictions conveyed on the title page. Understanding compression including crtp and quality of. This option uses stac software data compression, which compresses the data before it is sent to the storage device. Feb 24, 1994 stac, which is based in carlsbad, calif. Only a very small subset of all patents on data compression are mentioned here.
Furthermore software compression can be of two types, cpuintensive or memoryintensive. The data is decompressed on the flight while loading. The key innovation of pied piper is that they have purportedly invented a lossless compression algorithm e. Stacker was a program from stac electronics that featured the lzs compression algorithm that was known for being pretty fast. Looking for online definition of stac or what stac stands for. Stacker could even compress your c drive then swap the virtual dc at runtime. Choose the backup job under backup options storage compression. But digital research bundled a version of superstor disk compression software with version drdos 6. Is a compression company like pied piper ever feasible in the real world. The verdict may help nudge the balance of power in the computer software industry. Stac is listed in the worlds largest and most authoritative dictionary database of abbreviations and acronyms stac what does stac. Jan 07, 2017 ram compression also referred to as virtual memory compression and memory compression is a memory management technique that utilizes data compression to reduce the size or number of paging requests to and from the auxiliary storage. Stac compression article about stac compression by the free.
Cisco 700 series isdn access routers cutter networks inc. Parties are deep into increasingly tense negotiations as to access to or use of intellectual property or customer lists that seem to go on for months, sometimes years and then the negotiations break down. The waterworth patent is now owned by stac inc, which won a lawsuit against microsoft, concerning the compression feature of msdos 6. Both software feature sets support stac compression to reduce usage costs. It was originally developed by stac electronics for tape compression, and subsequently adapted for hard disk compression and sold as the stacker disk. They claim to be able to compress everything and deliver it to the users device. Finally, although not strictly a stac feature, i adapted for tape several titles that. With high bus voltage and high current output, stac6 drives provide even the largest step motors with enough power to get the job done. Founded in 1983 and located in san diego, stac software, inc. Data compression condenses large files into much smaller ones. Data compression can be broadly classifed into hardware and software compressions. Solution designers face dozens of new software and hardware products. The compression type is available under tools options backup compression type in the backup exec.
Instead, stac s patents are for particular algorithms mathematical formulas for squeezing a quart of data into a pint container. Stacker compression is based on the lempelziv compression algorithm. You can use the lzo compression scheme or the gzip compression scheme. Stac testing tools stac insight for the algorithmic. Data compression provides a coding scheme at each end of a transmission link that allows characters to be removed from the frames of data at the sending side of the link and then replaced correctly at the. Hardwareoptions field includes the following options. The recently posted 1718 pub output reports based on stacs for the 1617 enrollment year switched from using approval stac data to verified and locked stac data as of july 11.
History of lossless data compression algorithms engineering. It was true when our hard drives were tiny, and the advent of the internet has just made it more critical. The jury also agreed with a microsoft counterclaim that stac had misappropriated the microsoft trade secret of a preloading feature that was included in stacker 3. Lempelziv stac lzs, or stac compression is a lossless data compression algorithm that uses a combination of the lz77 slidingwindow compression algorithm and fixed huffman coding. Software compression basically uses stac storage allocation and coding program and compresses data before its copied to the media drive. Various types of compression algorithms are in use in the world today. Stacker compression is based on the lempelziv compression. The ace doublecard is a ram card that comes with a preinstalled, readytogo version of stacker for the 95lx.
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