Xserve was a line of rack unit computers designed by Apple Inc. for use as servers. When the Xserve was introduced in 2002, it was Apple's first designated server hardware design since the Apple Network Server in 1996. It initially featured one or two PowerPC G4 processors, but was later switched over to the then new PowerPC G5, and subsequently switched again to two quad-core Intel Nehalem microprocessors.
The Xserve can be used for a variety of applications, including file server, web server or even high-performance computing applications using clustering – a dedicated cluster Xserve, the Xserve Cluster Node, without a video card and optical drives was also available. On November 5, 2010, Apple announced that the Xserve line would be discontinued on January 31, 2011 and replaced with the Mac Pro Server and the Mac Mini Server.
Xserve G4 
The original Xserve G4
The second-generation Xserve G4
The Xserve G4 Cluster Node
|Release date||May 14, 2002|
|Discontinued||January 6, 2004|
|CPU||Single or dual PowerPC G4,
1 GHz – 1.33 GHz
Apple introduced the Xserve on May 14, 2002 (released in June). Originally, it had one or two PowerPC G4 processors running at 1.0 GHz and supported up to 2 GB of PC-2100 memory on a 64-bit memory bus. Three FireWire 400 ports (one in front, two in rear), two USB 1.1 ports (rear), an RS-232 management interface (rear), and a single onboard Gigabit Ethernet port (rear) were provided for external connectivity. Two 64-bit/66 MHz PCI slots and one 32-bit/66 MHz PCI/AGP slot were provided; in the default configuration the two PCI slots were filled with an ATI Rage video card and an additional gigabit Ethernet card. Up to 4 UATA/100 hard disk drives (60 or 120 GB) fit into hot-swap bays in the front, allowing software RAID-0 and 1 arrays to be created. A tray-loading CD-ROM drive was mounted in the front.
Initially, two configuration options were available: a single-processor Xserve with 256MiB of memory at $2999 and a dual-processor Xserve with 512 MiB of memory at $3999. Both shipped with a single 60 GB disk and models before August 24. 2002 shipped with Mac OS X v10.1 "Puma" Server, after August 24, 2002 shipped with Mac OS X v10.2 "Jaguar" Server.
On February 10, 2003 Apple released an improved and expanded Xserve lineup. Improvements included one or two 1.33 GHz PowerPC G4 processors, two FireWire 800 ports (rear), faster memory (PC-2700), and higher capacity Ultra ATA/133 hard disk drives (80 or 160 GB). Also, the front plate was redesigned for a slot-loading CD-ROM. A new model, the Xserve Cluster node was announced at the same price as the single-processor Xserve, featuring two 1.33 GHz processors, no optical drive, a single hard drive bay, no video or Ethernet cards, and a 10-client version of "Jaguar" server.
On April 2, 2003 the Xserve RAID was introduced, providing a much higher capacity and higher throughput disk subsystem for the Xserve.
Xserve G5 
The Xserve G5
The Xserve G5 Cluster Node
|Release date||January 6, 2004|
|CPU||Single or dual PowerPC G5,
2 GHz – 2.3 GHz
On January 6, 2004 Apple introduced the Xserve G5, a redesigned higher-performance Xserve. The 32-bit PowerPC G4s were replaced with one or two 64-bit PowerPC 970 processors running at 2 GHz. Up to 16 GiB of PC-3200 ECC memory was supported on a 128-bit memory bus. One FireWire 400 port (front), two FireWire 800 ports (rear), two USB 2.0 ports (rear), an RS-232 management interface (rear), and two onboard gigabit Ethernet ports (rear) with TCP offload provided greater connectivity. A 133 MHz/64-bit and a 100 MHz/64-bit PCI-X slots rounded out its expansion options. Ventilation issues restricted it to three SATA hot-swap drive bays (80 GB or 250 GB each), with the original space for the fourth drive bay used for air vents. The front plate and slot-loading optical drive (CD-ROM, DVD-ROM/CD-RW optional) were retained from the last Xserve G4.
Three configuration options were available: a single-processor Xserve G5 with 512 MiB of memory at $2999, a dual-processor Xserve G5 with 1 GiB of memory at $3999, and a dual-processor cluster node model (with an unchanged appearance from the G4 cluster node) featuring 512 MiB of memory, no optical drive, a single hard drive bay, and a 10-client version of "Panther" Server at $2999.
The higher memory capacity and bandwidth of the Xserve G5 as well as the stronger floating-point performance of the PowerPC 970 made it more suitable for high-performance computing (HPC) applications. System X is one such cluster computer built with Xserves.
On January 3, 2005, Apple speed bumped the Xserve G5 with 2.3 GHz PowerPC 970 processors in the dual-processor configurations. 400 GB hard disks were made available for up to 1.2TB of internal storage. The slot-loading optical drive was upgraded to a combination DVD-ROM/CD-RW standard, DVD-/+RW optional.
Soon after, Apple updated the Xserve and Xserve RAID to allow the use of 500 GB Hard Drives.
Intel Xserve 
The Xserve "Xeon"
|Release date||November 2006|
|Discontinued||January 31, 2011|
|CPU||Single or Dual Intel Xeon 5500 Quad Core CPU's, 2.26 GHz – 3.33 GHz|
|Memory||Up to 48 GB DDR3 1067 MHz Ram (12 DIMM slots)|
The Intel-based Xserves were announced at the Worldwide Developers Conference on August 7, 2006, and are significantly updated compared to the XServe G5, and G4. They use Intel Xeon ('Woodcrest') processors at 2 GHz, 2.66 GHz, or 3 GHz, PC2-5300 (DDR2-667) ECC FB-DIMMs, ATI Radeon X1300 graphics, a maximum storage capacity of 2.25TB when used with three 750 GB drives, optional redundant power supplies and a 1U rack form factor. The Intel Xserves now had their graphics cards on board, meaning that one did not need to sacrifice a PCI slot to add video capabilities — a departure from G4 and G5 Xserves.
On January 8, 2008 Xserve was updated to use Intel Xeon ('Harpertown') processors at 2.8 GHz or 3 GHz, PC2-6400 (DDR2-800) ECC FB-DIMMs, and a maximum storage capacity of 3TB when used with three 1TB drives. The front mounted FireWire 400 port featured in previous models was also replaced with a USB 2.0 port.
The Xserve RAID was discontinued on February 19, 2008.
On April 7, 2009 Xserve was updated to use Intel Xeon ('Gainestown') processors at 2.26 GHz, 2.66 GHz or 2.93 GHz, PC3-8500 (DDR3-1066) ECC DIMMs, two FireWire 800 ports, and a NVIDIA GeForce GT 120 graphics with 256 MB of GDDR3 memory and Mini DisplayPort output. The update also saw an increase to the maximum retail storage capacity, bringing it from 2TB to 6TB when used with three 2TB drives. An option to add a 128 GB SSD boot-drive that does not occupy a drive bay was also implemented. The addition of the optional detected boot drive that does not use a drive bay allows all drives to be swapped whilst the server remains online. It was also Apple's first Xserve to use PVC-free internal cables and components and contain no brominated flame retardants.
On August 28, 2009 Xserve was updated to ship standard with Mac OS X Server 10.6 Unlimited Client Server. In addition to improved functionality Mac OS X 10.6 Server added support for up to 96 GB of RAM (a configuration which is not currently supported by the Xserve system-board).
On November 5, 2010, Apple announced that it would not be developing a future version of Xserve. While accepting orders for the current model until January 31, 2011, and honoring all Xserve warranties and extended support programs, the company suggested users switch to Mac Pro Server or Mac mini Server.
|Timeline of Macintosh servers|
- "Xserve Transition Guide". 5 November 2010. Retrieved 5 November 2010.
|Wikimedia Commons has media related to: Xserve|
- Apple Server Documentation
- Apple Xserve G5 Developer Note
- Apple Xserve G4 Developer Note
- Intel Xserve Complete Disassembly