A: AcomData 509 Drive Enclosures are compatible with most Windows PCs and Macintosh computers. For Windows PCs you will need a computer with a minimum 233 MHz Pentium (or equivalent processor, such as Celeron, AMD etc.), running Windows 98SE, ME, 2000, or XP. For Macintosh you will need a Mac or Power Mac running Mac OS 9 or OS X.

A: No. A drive can only 'talk' to one computer at a time. If you connect the 509 to two computers, you may damage the drive and/or your computers.

A: If the IDE/EIDE drive you plan to install into a 509 Enclosure is already formatted for your operating system, you will not need to format the drive. You can simply install the drive and begin using it right away. (Follow the instructions in the User's Guide.) If your drive is NOT formatted, follow the insructions in the User's Guide to properly install the drive and then format it.

A: It is possible to format a hard drive for use on both Mac and PC platforms. Full instructions are in the User's Guide.

A: It is possible to use an external drive as a startup disk (boot volume) on Mac OS 9 and Mac OS X. Follow the instructions in your Mac OS manual for the proper installation of the Mac OS. If you wish to use your drive as a startup disk, make sure you install the Mac OS on the drive before saving any data to the drive. On Windows operating systems it is not possible to use an external hard drive as a boot volume.

A: Yes, the 509 does support 48-bit LBA. The capacity limit of 48-bit LBA is 144 petabytes (144,000,000 gigabytes), certainly more than enough for today's hard drives.

The original design specification for the ATA interface only provided 28-bit addressing, limiting drive capacity to 137.4 GB. 48-bit LBA extends the capacity of IDE ATA/ATAPI devices beyond this limit. Some versions of Microsoft Windows do not support hard drives greater than 137 GB; other versions do but it may be necessary to update the operating system with the latest Service Pack and a parameter may need to be defined and set properly in the Windows registry. There's also an issue with the BIOS where it may be necessary to install a BIOS upgrade for your system in order for the system to work properly with the new hard drive.

A: You cannot transfer an installed operating system to another computer or hard drive simply by copying the operating system files. In order to install an operating system, you'll need to follow the manufacturer's installation procedure. If you wish to transfer the contents of one boot volume (drive) to another, you will first need to properly install the operating system on the target drive. You can then use an external drive to copy over your files (except the operating system).

A: FAT32 is an older and more compatible file system but it has certain limitations, such as file size (maximum 4 GB). NTFS is more secure and has fewer limitations. The NTFS file system can only be used on Windows 2000 and XP. If you plan to use your drive on Windows 2000 and/or XP only, you may want to consider re-formatting the drive using the NTFS files system. If you plan to use the drive on a Mac OS only, and you do not need Windows compatibility, you may want to consider re-formatting the drive using a Mac OS Extended file system. Refer to the User's Guide for instructions.

A: For USB 2.0 on Windows 98SE, you will need to install the USB 2.0 driver found on the supplied USB 2.0 Installation CD. The driver is also available for download on AcomData support page. All other supported operating systems have the necessary USB 2.0 drivers built in, with the exception of Mac OS 9, which supports USB 1 but not USB 2.0. You can connect the drive to a USB 1 port, but it will operate at USB 1 speeds (up to 12 Mbps). Depending on your operating system, you may need to download an update from the OS manufacturer.

A: USB (Universal Serial Bus) is an interface technology for the serial transmission of digital data. The original standard (USB 1) could transmit data at speeds of up to 12 Mbps (Megabits per second), which equals 1.5 MB/s (Megabytes per second). USB 2.0 has a maximum throughput of 480 Mbps (60 MB/s) – up to 40 times faster than USB 1. At that speed it is possible to transfer a full GB (Gigabyte) of data in less than 18 seconds.

USB is a master-slave, host-based technology, meaning USB devices need to be connected to a computer, either directly or indirectly via a USB hub in order to communicate with each other. The computer dictates data flow to, from, and between attached USB devices. While 480 Mbps is the maximum speed, data transfer rates will vary depending on a number of factors, including available CPU resources.

The USB standard supports up to 127 devices. Connecting more than one or two USB devices to a computer typically requires the use of one or more hubs, where each hub can accommodate several USB devices.

The maximum allowable length of a USB cable is 5 m (16.4 ft.). USB can supply on-bus power of up to 2.5 W. This means that many low-power-consumption devices, such as flash card readers do not need to be plugged into an electrical outlet because they can get sufficient power via the USB cable. More power-hungry devices, such as hard drives, still require a separate electrical connection for power.

USB is a plug-and-play and hot-swappable technology. You do not need to assign ID numbers, or connect terminators. On most operating system you do not need to install drivers because the necessary drivers are built into the operating system. Devices can be added and removed while the computer is running. Also, you can turn off the device when not needed, in order to conserve electricity.

A: FireWire is a serial data input/output technology developed by Apple Computer and Texas Instruments. The first FireWire standard was approved by the Institute of Electrical and Electronic Engineers (IEEE) in 1995.

FireWire 400 can transmit data at up to 400 Mbps (50 MB/s). FireWire 800 can transmit data at up to 800 Mbps (100 MB/s). FireWire supports both isochronous and asynchronous data transfers. Isochronous mode provides guaranteed transmission of data at defined intervals; it’s used when delayed or out-of-order data frames are unacceptable, such as for capturing digital video. In asynchronous mode the intervals between transmissions can vary, and data can be resent if missed. Asynchronous mode is typically used for routine data transfers.

FireWire devices can be linked in a daisy-chain, where the devices are connected to each other in series. A hub is only required when a very large number of devices will share the same FireWire bus. With the use of FireWire hubs, up to 63 devices can be linked on a single FireWire bus.

FireWire devices are host-independent, meaning data transmissions between FireWire devices on the same bus can take place without the need for input from the host computer. This lack of dependence on the host is one of the reasons FireWire devices are on average faster than USB 2.0 devices in routine day-to-day use, even though the rated maximum data transfer is lower than that for USB 2.0.

Standard FireWire 400 cables use 6-pin connectors at both ends. FireWire 800 cables use 9-pin connectors. Cables with 4-pin connectors are also available for connecting FireWire devices to laptop/notebook computers and other devices that have 4-pin ports.

FireWire can supply up to 45 W of electrical power, making it possible to use many low-power-consumption devices without a dedicated electrical connection. (FireWire cables with 4-pin connectors cannot transmit electrical power.) When a device is powered via FireWire, power is delivered only when actually needed.

You do not need to install drivers, assign unique ID numbers, or connect terminators.

FireWire devices can be connected to or disconnected from the computer while the computer is running. Always dismount a hard drive before turning off and disconnecting it.

A: As with so many questions about technology, the answer to that question is not a simple one. USB 2.0 and FireWire are very similar in many respects, but there are definite differences.

At first glance it would appear that USB 2.0 (480 Mbps) is indeed faster than FireWire (400 Mbps). However, this is only true under ideal conditions. While 480 Mbps is the maximum speed achievable, USB 2.0 cannot guarantee a specified data transfer rate. This is mainly because USB 2.0 is a master-slave, host-dependent technology, meaning it relies on your computer's CPU to facilitate and manage data transfers.

FireWire (IEEE 1394x), on the other hand, is a peer-to-peer technology that does not require CPU resources to facilitate data transfers between FireWire devices. Moreover, FireWire devices can guarantee real-time delivery of data at a specific rate. Real time data delivery is necessary for certain applications, such as digital video streaming where dropped or delayed data packets is unacceptable. This is why devices like digital camcorders have 1394 interfaces, and why FireWire is the interface of choice for digital video editing applications.

For day-to-day hard drive use, USB 2.0 and FireWire will have comparable performance though FireWire will probably have a slight performance edge, which can make a difference if you are performing tasks that require large, frequent data transfers.

A: A drive's cashe resides on the circuit board integrated into the IDE/EIDE drive unit. To check the cache size of your drive you will need to refer to the manufactuer's specifications.

A: Efficient dissipation of heat generated by a hard drive's internal components is important for reliability and long life. The 509 Enclosure has been engineered to be so efficient at dissipating internal heat that it does not need a fan. Aside from consuming less electricity, the added benefit is virtually silent operation.

A: The capacity of a hard drive will appear slightly less in Windows and Mac operating systems than the capacity stated by the hard drive's manufacturer. This is not only the case for AcomData drives but is typical in the data storage industry. The difference is mostly due to the way Windows and Mac operating systems typically measure data storage, as compared to the method used by hard drive manufacturers.

Hard drive manufacturers have always used the decimal (base 10) number system to measure the storage capacities of hard drives. In the decimal system 1GB = 1,000 MB = 1,000,000 KB = 1,000,000,000 bytes. Windows and Mac operating systems use the binary (base 2) method, where 1GB = 1,024 MB = 1,048,576 KB = 1,073,741,824 bytes. Example: A hard drive with a capacity of 120 GB (decimal) will show up on Windows and Mac with a capacity of say 111.8 GB (binary). The actual number of bytes is 120,044,335,923, which is just over 120 GB (decimal).

Hard drive manufacturers use the decimal method because it is the number system we are all familiar with in our daily lives. Using the decimal method is simpler and less confusing to the average consumer than the binary method for converting kilobytes to megabytes to gigabytes and so on. Manufacturers of operating systems do not need to concern themselves with this issue, so they typically use the more traditional binary method. But as long as the drive displays the correct number of bytes (approximately), you are getting the drive’s full stated capacity. The reason the actual number is approximate is because operating systems reserve a small amount of disk space for their own purposes; the actual amount can vary from operating system to operating system.

A: Yes, but only with Norton Ghost 2003.

A: AcomData does not provide data recovery services. You will need to send the drive to an authorized data recovery company. We recommend Ontrack at 800.872.2599. Once you have recovered your data, email or call Tech Support to obtain warranty service.