The PCI Ultra SCSI JackHammer·SE (or JackHammer) is a high performance, single-ended, accelerated PCI to SCSI host adapter card that dramatically increases performance of SCSI devices connected to it.
The JackHammer is a PCI device that creates a high-speed interface between the CPU and disk drive. The JackHammer can transfer data though the Ultra SCSI-3 portion of the card at 40MB/sec (as allowed by the SCSI-3 specification). The PCI portion of the card is capable of data transfer rate bursts up to 132MB/sec. This means that your Workgroup Server 9650 can receive data as fast as your drives can provide it. Simply connecting the JackHammer to your SCSI drives improves their overall performance.
JackHammer ships pre-installed in the Mac OS-based Workgroup Server 9650. To ensure the best possible disk I/O performance, the Workgroup Server 9650 ships with all internal hard drives attached to the JackHammer card. The Workgroup Server 9650 allows for a total of four internal Ultra devices. Due to electrical signal limitations with Ultra devices, Apple does not recommend connecting external devices to the JackHammer.
In addition the Workgroup Server 9650 ships with the PCI SCSI JackHammer Control Panel v1.2.2 pre-configured on the server's boot drive. If for some reason you need to re-install the JackHammer Software, the CD-ROM you received with your Workgroup Server 9650 includes an installer that automatically loads all the software files needed for the JackHammer.
How the JackHammer Improves Performance
Once configured, the JackHammer operates transparently. As a user you will immediately notice faster data transfers and increased productivity. For example, the JackHammer can speed up file saves in popular programs, such as Adobe PhotoShop or Claris FileMaker Pro, by 50 percent or more. You will also notice performance increases in other disk-intensive procedures, such as general database use, image rotation, video capture, or software compiling. The JackHammer improves performance in two ways:
- By eliminating the standard SCSI bottleneck
When you install the JackHammer, a high-speed SCSI bus is added to your computer. This new SCSI bus complements -- but does not disable -- the native SCSI bus(es). The JackHammer lets your computer sustain data transfer rates at the full speed of the drive, eliminating the constraints and restrictions of older generation SCSI controller chips. The JackHammer supports 16-bit, 40 MB/s, SCSI-3 data transfers.
- By providing on-board intelligence
The JackHammer features bus mastering. Each JackHammer card has an embedded RISC-based, 30 MIPS (Million Instructions Per Second) microprocessor. This microprocessor processes reads and writes requests to and from a SCSI device without main logic board supervision. The JackHammer's microprocessor frees the computer to manage other tasks and increases overall system performance. It also provides automatic termination when the JackHammer is at either end of the SCSI bus chain.