Not so much a review for GSX but a review for its successor which is known simply as Vmware Server.
First off is to tell you that VMware server is a free downloadable vitrualisation software, and although not officially supported it will run happily on a windows XP or Vista desktop computer where it can be used like a cutdown version of VMware Workstation.
For those who don't know what vitualisation is I will explain, Virtualisation is the running of various operating system/software on virtual hardware which is created by software within a host operating system i.e. a computer can be running windows XP which in turn is running VMware which simulates computer hardware that is in turn running Windows server 2003 and/or running one of the varios flavours of linux. Yes you did read "and/or" which indicates that you can successfully (if you have enough memory/disk/cpu) run more than one virtual machine on a single host.
Virtualisation has many uses which include:
1. being able to test and evaluate a differnet operating system before placing it on real hardware
2. being able to run software that ordinarily wouldn't run on your operating system.
3. Consolidation - A corporate use where multiple different servers are relocated onto several virtual server hosts, thus reducing the number of physical boxes and reducing overheads such as power required to run them, cool them, and space required to house them.
4. Development - a way of testing software and programs in a test environment so as to not break the live systems
VMware are one of a number of producers of software that allows for this type of virtualisation and they offer several flavours of there software which are VMware workstation, GSX Server (now just Server) and ESX server.
VMware workstation is designed to fill points 1,2,4 and is designed to be run on a Windows, Linux or Mac desktop host that is not a server operating system (although it can be installed on server OS). It has a cost per license and includes lots of features. Features include multiple snapshots (points in a VM's life cycle which can be returned to), USB passthrough (so memory sticks and other devices can talk directly to the VM), and more recently advance graphics support which allows for advanced 3D effects to be run on VM's where the host hardware supports it (this currently only works for windows guests).
ESX and GSX were designed to forfil all the points but primarily point 3. GSX was designed to run on Server platforms and host server operating systems so as to consolidate hardware.
GSX doesn't support features like usb pass through, advanced graphics support or multiple snapshots (you can take 1 per VM) as such features are either unessacery or include a performance hit that would be unwanted in a production environment (Live servers). GSX does offer features such as automatic starts (run VM's as services that start automatically), mulitple admin conections, lots of virtual disks.
ESX which is the large scale enterprise version goes even further by running what is known as a hypervisor on a very lightweight debian linux kernal which bring huge performance benifits, it also doesn't have support for enhance graphics, or usb passthough although it does support multiple snapshots. It does though allow for a host of advanced features such as Vmotion (allows you to move a virtual server from one host to another whilst it is switched on and running) High Availability (HA) which allows you to configure servers to automatically rebooted on another server in the event of a host failure, DRS which monitors servers performance and suggests/automatically moving VM's to different hosts to maintain the best server performance, and a host of other features.
Anyway until ESX became the main player in the corporate world VMware GSX server was an expenseve software, however VMware have realised that they can better intise businesses to start using their software by giving GSX away for free in the hope, that once the benifits are seen, the companies will buy the ESX software.
This means that the software can also be used by students, home users and IT staff who may have a need for it in order to do testing. The download is a couple of hundred MB and the install reletively painless.
Configuring a machine is relatively easy and can be done by creating a new machine, telling the server the type of machine you are building (eg linux, windows) setting memory allowances, creating a virtual hard disk (vmdk), pointing the virtual CD drive at the install media and powering the machine on.
One thing to note is that you will need to have a lot of RAM and hard disk space on your computer to accomodate the virtual machines.
As a free software VMware Server is a great product and has a great deal of functionality.
If you are curious about linux but don't want to abandon Windows just yet then install this and try the latest Linux distro, if you then like it but think you can't live without some windows functions you could even do a complete swap and run Linux as the host and Windows as the guest as Linux can run VMware as well.