Data compression condenses large files into much smaller ones. District court found that the datacompression technology contained in microsofts msdos 6. History of lossless data compression algorithms engineering. Stac did not invent data compression, which dates to the 1940s. Fiala and greene obtained in 1990 a patent 4,906,991 on all implementations of lz77 using a tree data structure. Both software feature sets support stac compression to reduce usage costs. Founded in 1983 and located in san diego, stac software, inc. Solution designers face dozens of new software and hardware products. Hardware compression option 1 backs up the data uncompressed then runs an nt compression program on the data whilst on the backup media.
The verdict may help nudge the balance of power in the computer software industry. With ondemand access to safety, training, and certifications via the stac card or stac sticker instant. It was originally developed by stac electronics for tape compression, and subsequently adapted for hard disk compression and sold as the stacker disk. This document describes the use of the stac lzs data compression algorithm, with single or multiple compression histories, for compressing ppp encapsulated packets. The doublecard also lets you compress your 95lxs c drive. For auxiliary copy operations, data is copied in the compressed state. Cisco 700 series isdn access routers cutter networks inc.
Understanding compression including crtp and quality of. For compression, a scope needs to be set ahead of time. 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. Choose the backup job under backup options storage compression. Aug 14, 2018 software engineers have always developed new ways of fitting a lot of data into a small space. Benefits when you own a cisco 700 series access router, you have a.
Furthermore software compression can be of two types, cpuintensive or memoryintensive. Data compression internet ready ip 30 yes remote of. Looking for online definition of stac or what stac stands for. Stacker would create a file on your disk, then present that file as a virtual disk that your programs could run. It enables reducing the storage size of one or more data instances or elements. The size of the award was based on estimated royalties for stac s data compression program. General options for backup jobs and templates symantec. 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. Stacker could even compress your c drive then swap the virtual dc at runtime. That paper was a byproduct of an initiative in the stac big data sig to develop technologyagnostic benchmarks based on big data workloads. You can use the compress stac software command to force the use of software compression. Configuring compression on a serial interface with a command such as compress stac automatically enables hardware compression if it is available.
Jan 09, 2009 there are 2 data compression types in backup exec. Instead, stac s patents are for particular algorithms mathematical formulas for squeezing a quart of data into a pint container. Lucent technologies model number comcode description price pipeline 15 isdn bri products p751sbriasa 408046035 pipeline 75 with ipipxappletalk routing, stac 4. Each stac test harness embodies the industrys best practices in four areas. It is known primarily for its lempelzivstac lossless compression algorithm and stacker disk compression utility for compressing data for storage. This option uses hardware data compression if the storage device supports it. The stac training tracking software provides accountability, reliability and verification in matters relating to safety, training, and certifications. Is a compression company like pied piper ever feasible in the real world. Gzip is the default compression scheme, but you can use an additional setting to change the compression scheme on a client.
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. Hence, if the compression is performed using any version of backup exec, there. 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. A data compression technique from stac, used with modems. 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. Stac compression article about stac compression by the. Backup exec compression types deciphering lifes source code.
Hence, if the compression is performed using any version of backup exec, there will be no issues while restoring the same data. 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. Stacker compression is based on the lempelziv compression. Hardware if available, otherwise none uses hardware data compression if the storage device supports it. 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.
The stac6 series stepper drives are powerful, twophase, bipolar step motor drives for highspeed, hightorque applications. Feb 24, 1994 stac, which is based in carlsbad, calif. Stac big data sig stac insight for the algorithmic. Jan 15, 2008 data compression reduces the size of data frames to be transmitted over a network link.
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. The compression type is available under tools options backup compression type in the backup exec. Few areas cry out for good technology benchmarks more than the wild west of big data. Stacker was a program from stac electronics that featured the lzs compression algorithm that was known for being pretty fast. Microsoft settles patent dispute with stac, agrees to license. The key innovation of pied piper is that they have purportedly invented a lossless compression algorithm e. The doublespace data compression system, which comes free with. Cisco 700 series isdn access routers cisco 700 series integrated services digital network isdn.
Uses stac software data compression, which compresses the data before it is sent to the storage device. This slide is subject to the proprietary restrictions conveyed on the title page. Stac compression is capable of compressing data by a factor of about four explanation of stac 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. Stac, in an effort led by attorney morgan chu, sued microsoft for infringement of two of its data compression patents, and won. Stacker file compression software and the ace doublecard 2. 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. Software compression basically uses stac storage allocation and coding program and compresses data before its copied to the media drive. If the drive does not feature data compression the data is backed up uncompressed. Hardwareoptions field includes the following options.
Microsoft settles patent dispute with stac, agrees to. A stac test harness is software that enables the execution of stac benchmarks. Stac compression is capable of compressing data by a factor of about four. Stac testing tools stac insight for the algorithmic. 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. This option uses stac software data compression, which compresses the data before it is sent to the storage device. 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. Stac software tape turbo with error recovery sources. I run it three times and got three different compression ratio. The ace doublecard is a ram card that comes with a preinstalled, readytogo version of stacker for the 95lx. I have 2 sites connected via 64kbps serial link routers 3620 running ios 12. It is known primarily for its lempelziv stac lossless compression algorithm and stacker disk compression utility for compressing data for storage.
Is a compression company like pied piper ever feasible in the. Is a compression company like pied piper ever feasible in. 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 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. This type solely uses the nt hardware compression technology. Stac also implements a simple zero cost rle compression. The company builds on these advancements to create highperformance systems recovery software solutions to protect businesscritical data. Reducing the size of a frame reduces the time required to transmit the frame across the network. Without data compression a 3 minute song would be over 100mb and a 10 minute video would easily be over 1gb. Software compression is available for all storage media. If the drive does not feature data compression, the data is. Mar 06, 1994 stac did not invent data compression, which dates to the 1940s. Mp3, mp4, rar, zip, jpg and png files along with many others all use compressed data.
Finally, although not strictly a stac feature, i adapted for tape several titles that. The ppp compression control protocol 2 provides a method to negotiate and utilize compression protocols over ppp encapsulated links. Stac electronics, originally incorporated as state of the art consulting and later shortened to stac, inc. Various types of compression algorithms are in use in the world today. I choose 8192 bytes icmp to test the compression and got below results. 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. 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. Hello i have enabled stac compression on hdlc serial link.
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. They claim to be able to compress everything and deliver it to the users device. Stac compression article about stac compression by the free. An explanation of hardware and software compression used with backup exec how does compression work. Stac is listed in the worlds largest and most authoritative dictionary database of abbreviations and acronyms the free dictionary. It was true when our hard drives were tiny, and the advent of the internet has just made it more critical. 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. But as it turned out, the compression technology worked really well in software form, too. It has been a busy few months for stac electronics inc, the carlsbad, californiabased data compression company. Data compression is also known as source coding or bitrate reduction. The data is decompressed on the flight while loading. But digital research bundled a version of superstor disk compression software with version drdos 6.
Software based exar lempleziv stac lossless data compression and decompression algorithms. 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. Previo, hp roll out network appliance computerworld. The backup exec includes two data compression types. Only a very small subset of all patents on data compression are mentioned here. 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. You can use the lzo compression scheme or the gzip compression scheme. The waterworth patent is now owned by stac inc, which won a lawsuit against microsoft, concerning the compression feature of msdos 6. With high bus voltage and high current output, stac6 drives provide even the largest step motors with enough power to get the job done. Stacker compression is based on the lempelziv compression algorithm. Stac is listed in the worlds largest and most authoritative dictionary database of abbreviations and acronyms stac what does stac. 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.
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