Concept Overview

Figure 1 - PHMS Overview

The basic operation of PHMS is centered around the server-client model as seen in Figure 1. To paraphrase, the server is the data storage mechanism. Data is not saved in files or in "shared" folders - it is stored by the server. On the other hand, the client is responsible for retrieving a given set of data from the server and presenting it to the operator in a human friendly way. Multiple clients may interact with the data on the server simultaneously.

The most important requirement is that the database server be installed on one and only one machine. You will not be able to share data if you have more than one database server installed.

There is no requirement for the server and the client part to be installed on separate computers. Actually, the most straight forward installation is for the client and the server to reside on the same machine.

Secondly, there is no requirement that the server is installed on a computer running special "server" version of Windows. Any regular computer will do. What is recommended is that the database server is deployed on a machine with redundant storage. For example, a RAID 1 hard drive configuration is a perfect choice. It allows for hard drive failure without any downtime or data loss.

Finally, the is no requirement that the computer running the server is a dedicated machine. On the contrary, it would be wasteful to have a dedicated machine if you already have another computer that can do the job. In a normal environment, the database server will use very little resources and thus if you already have a file server with redundant storage, it makes sense to also use that computer as the PHMS database server.

The only requirement that must be satisfied for PHMS to work is that it must be able to connect with the database server to retrieve data. There is no "local" or "remote" automagical sense built-in to PHMS. If it cannot access the server, it cannot retrieve, edit, or even login to the database. There is no requirement on how the connection is to be made between PHMS and the database server. For example, Figure 2 shows a little bit more complicated interface to PHMS than in Figure 1. There may be multiple PHMS users, some connected to the database over wireless LAN or VPN (Virtual Private Network) or even dial-up. The solution that would be ideal for your center is beyond this short overview, but your IT department should be able to provide you with a secure remote or local connection between PHMS and the database server.

Figure 2 - More complicated installation

In conclusion, an ideas server will be,

  • secure - a computer with relatively good physical security (not a laptop). If your server gets stolen, so does your entire patient database.
  • reliable - redundant storage should be used to minimize the chance of downtime and data loss in case of hardware failure.
  • accessible - all computers running PHMS must be able to access this server for their data.
  • backup - please, backup your data. Your server can blow up, crash, catch on fire, corrupt its file system, etc. There is no excuse for not setting up an automated backup. For more information see Setting up Automated Backup.

The PHMS client is just an interface between you and the server. Protect the server as that is where you data resides. On the other hand, PHMS client software is 100% replaceable.

If you would like to have multiple PHMS clients installed on different computers having access to the database server, the database server must have a static IP.

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