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Resources > Technical Specifications > System Architecture
The architecture of a system encompasses the hardware and software used to deliver the solution to the final consumer of services. The system at QualityTools, sponsored by the Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services, consists of four (4) complementary subsystems:
QualityTools runs on the Microsoft software platform. All of the servers (Web, database and e-mail) run on Windows 2000. The database servers are running Microsoft SQL Server 2000 and are running backups and Trend ScanMail for virus prevention. The Web servers are running Microsoft Internet Information Server (IIS) 5.0 and the Web pages are written in Microsoft VB.NET.
The hardware platform consists of a variety of resources. The servers are custom-made, low-cost, high-speed AMD-based computers. We are running the Tyan Tiger and Thunder motherboards with dual AMD Athon 2200+ MP processors. The database servers have 4 GB of 266 DDR memory and the Web servers have 2 GB of 266 DDR memory. All production servers are running Seagate 15K SCSI drives. The content development servers and e-mail servers run the 3Ware IDE 64bit 8-port RAID controller with IBM IDE high-capacity drives running at 7200 RPM. The client content-development machines range from generic Celeron-based PCs running with 32 MB of RAM and 4 GB of hard-drive storage to Compaq Pentium IV 2800 machines with 1 GB of 266 DDR RAM and IDE drives with 120 GB of storage. The QualityTools project uses the Cisco Local Director appliance to load balance the Web traffic across multiple Web servers.
The content development environment consists of a custom Microsoft Visual Basic (VB) 6.0 application has been tested on Windows 98 SE, Windows NT 4.0, Windows 2000 (Professional and Server) and Windows XP (Home and Professional). The tool has also been used in a TCP/IP LAN environment and where the client machine is remotely attached via a 56K modem through the Internet.
The Internet publishing process runs using the native task management facilities of SQL Server 2000 and Windows 2000. The publication process copies the subset of information that has received final approval for publishing to the publishing servers. These publishing servers run the same Windows 2000 platform with IIS 5.0 and SQL Server 2000 as the content development environment. In order to track usage of the site, the QualityTools uses Site Server Analysis to prepare Web site usage reports. QualityTools has a L-Soft ListServ list available at QualityTools-L@lists.ahrq.gov.
The system monitoring and control framework consists of custom web pages which retrieve and display the status of the content development inventory as well as the various machine status conditions.
For questions, contact the QualityTools Web site administrator at webmanager@qualitytools.ahrq.gov.
