In computing, serial presence detect (SPD) is a standardized way to automatically access information about a memory module. Earlier 72-pin SIMMs included five pins that provided five bits of parallel presence detect (PPD) data, but the 168-pin DIMM standard changed to a serial presence detect to encode much more information.[1]
For a memory module to support SPD, the JEDEC standards require that certain parameters be in the lower 128 bytes of an EEPROM located on the memory module. These bytes contain timing parameters, manufacturer, serial number and other useful information about the module. Devices utilizing the memory automatically determine key parameters of the module by reading this information. For example, the SPD data on an SDRAM module might provide information about the CAS latency so the system can set this correctly without user intervention.
data rescue pc3 serial 18
The JEDEC standard only specifies some of the SPD bytes. The truly critical data fits into the first 64 bytes,[6][7][15][16][17] while some of the remainder is earmarked for manufacturer identification. However, a 256-byte EEPROM is generally provided. A number of uses have been made of the remaining space.
The header contains the following data. Most importantly, it contains a "medium timebase" value MTB, as a rational number of nanoseconds (common values are 1/8, 1/12 and 1/16 ns). Many other later timing values are expressed as an integer number of MTB units.
A not so common use for old laptops is as generic SMBus readers, as the internal EEPROM on the module can be disabled once the BIOS has read it so the bus is essentially available for use. The method used is to pull low the A0,A1 lines so the internal memory shuts down, allowing the external device to access the SMBus. Once this is done, a custom Linux build or DOS application can then access the external device. A common use is recovering data from LCD panel memory chips to retrofit a generic panel into a proprietary laptop.On some chips it is also a good idea to separate write protect lines so that the onboard chips do not get wiped during reprogramming.A related technique is rewriting the chip on webcams often included with many laptops as the bus speed is substantially higher and can even be modified so that 25x compatible chips can be read back for later cloning of the uEFI in the event of a chip failure.
Close behind these vendors but without the range of ancillary products is Cleverfiles. Its data recovery solution, Disk Drill, is a near-perfect budget solution for Windows PC users (the Mac version costs more).
The number of data recovery tools available numbers in the dozens. Some are powerful utilities aimed at IT professionals and other power users, while others are simple budget tools that might recover a deleted file in a pinch.
In order to find the best recovery options capable of handling just about any data loss scenario, we reviewed features and price plans while also performing preliminary testing. Only then did we settle on a handful of services we felt warranted deeper review in order to make the best recommendations to our readers.
Another feature not supported by Stellar that we like in Data Rescue is that the tool lets you create a bootable USB drive. This can be used to access data on a machine when its boot partition is corrupted.
The tool lets you run both quick and deep scans depending on your needs. Those scans can be used to recover deleted data or access corrupted, deleted or formatted partitions. In addition to your computer hard drive, you can recover data from external drives, SD cards and removable media. Optical media recovery is not an option, though.
One area where EaseUS stands out over our top two services (especially Data Rescue) is in how easy it is to sort through recovered data. You can browse through files based on your file structure or narrow things down based on file type.
The Wondershare Data Recovery wizard is simple but offers several great features to customize scans like the ability to scan by file type and scan specific folders. You can also choose to scan a labeled partition or pull data from the partition table to locate lost partitions.
In addition to recovering data from your Mac, Mac Data Recovery can pull data from Time Machine and encrypted disk drives. The tool is just as as attractive as its PC counterpart and just as suited to consumers and IT professionals, alike.
This bundle includes Drive Genius 4, a diagnostic tool to detect and correct hard-drive issues. You can use it to recover data from both PC and Mac, but the license is only good for one year, which a big reason to pick Stellar , instead.
Prosoft Eng. does have several other professional license bundles available, though, which might appeal to some. These include offerings with MediaTools Wipe, which is a tool that wipes drives completely clean of data.
Android data recovery tools let you recover deleted text messages, contact information, pictures and other content from your phone. Generally speaking, they work by attaching your phone to your computer via USB. However, some tools also give you a an app to recover data directly from the phone (we have a separate guide on how to recover data from a broken phone, in case you need it).
Dr. Fone has some added capabilities in addition to data recovery that help rank it ahead of EaseUS MobiSaver despite its higher price tag. These include rooting, SIM unlock, lock screen removal and data erasure. It can also be used to backup phone data to your computer.
What does a data recovery service company charge? Data recovery services usually price based on the severity of the issue. It can be quite expensive. U.S. electronics chain Best Buy, for example, charges between $200 and $1500 for professional recovery.
During our initial Cloudwards.net survey of the best data recovery tools available, we were both impressed by the number of good tools available and how much better the great tools were than the next tier.
This chapter is an introductory overview of the most commonly used assay methods to estimate the number of viable cells in multi-well plates. This chapter describes assays where data are recorded using a plate-reader; it does not cover assay methods designed for flow cytometry or high content imaging. The assay methods covered include the use of different classes of colorimetric tetrazolium reagents, resazurin reduction and protease substrates generating a fluorescent signal, the luminogenic ATP assay, and a novel real-time assay to monitor live cells for days in culture. The assays described are based on measurement of a marker activity associated with viable cell number. These assays are used for measuring the results of cell proliferation, testing for cytotoxic effects of compounds, and for multiplexing as an internal control to determine viable cell number during other cell-based assays.
Cell-based assays are often used for screening collections of compounds to determine if the test molecules have effects on cell proliferation or show direct cytotoxic effects that eventually lead to cell death. Cell-based assays also are widely used for measuring receptor binding and a variety of signal transduction events that may involve the expression of genetic reporters, trafficking of cellular components, or monitoring organelle function. Regardless of the type of cell-based assay being used, it is important to know how many viable cells are remaining at the end of the experiment. There are a variety of assay methods that can be used to estimate the number of viable eukaryotic cells. This chapter will provide an overview of some of the major methods used in multi-well formats where data are recorded using a plate reader. The methods described include: tetrazolium reduction, resazurin reduction, protease markers, and ATP detection. Methods for flow cytometry and high content imaging may be covered in different chapters in the future.
Because the real time reagent does not contain detergent (i.e. is non-lytic) and is well tolerated by most cell types, after recording viability data, the remaining sample of cells can be used for many downstream applications. Multiplexing can be achieved with a variety of other assay chemistries including: most assays with a fluorescent detection method, the luminescent ATP assay as an orthogonal approach to confirm viability data with more than one method, a luminescent caspase-3/7 assay to measure apoptosis, firefly reporter assays to monitor gene expression, and extraction of RNA that can be used to monitor gene expression.
Figure 20 illustrates an example showing the effect of a dose-response of a proteasome inhibitor on the viability of cells measured at different times from the same samples using the real time viability assay followed by multiplex measurement of ATP as an orthogonal method to demonstrate concordance between the two viability assays. The sequential multiplexing example shows results from recording luminescence from a shrimp-derived luciferase followed by recording luminescence from a firefly-derived luciferase. The ATP assay contains detergent to lyse cells to release ATP as well as luciferin and a stable form of luciferase necessary to measure ATP (see general description above in this chapter). The detergent lysis step stops the ability of cells to generate a substrate for the shrimp luciferase and thus diminishes the luminescent signal from the real time viability assay. This sequential combination of reagents makes it possible to record two luminescent signals from two different luciferases from the same sample. The 48 hour data from the real time assay approach agrees well with the 48 hour data from the ATP assay, demonstrating concordance between these two methods. Similar agreement between assays has been observed from the combination of the real time viability assay and a constitutive firefly reporter gene assay (not shown).
There are a variety of assay technologies available that use standard plate readers to measure metabolic markers to estimate the number of viable cells in culture. Each cell viability assay has its own set of advantages and disadvantages. The ATP detection assay is by far the most sensitive, has fewer steps, is the fastest to perform, and has the least amount of interference, whereas the tetrazolium or resazurin reduction assays offer less expensive alternatives that may achieve adequate performance depending on experimental design. The fluorogenic cell permeable protease substrate is far less cytotoxic than the tetrazolium and resazurin compounds while enabling many possibilities for multiplexing other assays to serve as orthogonal or confirmatory methods. The recently developed cell viability assay, based on generating a substrate for the shrimp luciferase, provides the opportunity for capturing data repeatedly in real time and offers many possibilities for multiplexing with other assays. Regardless of the assay method chosen, the major factors critical for reproducibility and success include: 1) using a tightly controlled and consistent source of cells to set up experiments and 2) performing appropriate characterization of reagent concentration and incubation time for each experimental model system. 2ff7e9595c
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