Network computer

A network computer is a lightweight computer system that operates exclusively via a network connection. As such, it does not have secondary storage such as a hard disk drive – it boots off the network, but runs applications locally, using its own CPU and RAM. This set NCs as distinct from terminals, which act as a client for an application server.

During the mid to late 1990s, some commentators and industry players such as Larry Ellison of Oracle Corporation, predicted that the network computer would soon take over from desktop PCs, and that many users would use applications loaded via a network instead of having to own a local copy.

So far, this has not happened, and it seems that the network computer "buzz" was either a fad or not ready to happen. The NC can be considered to be another computing paradigm. Just as PCs did not replace mainframes, so NC will not replace PCs. The new technology provides a more appropriate alternative in certain areas and can co-exist with established systems through open standards.

Distinction between NCs and terminals

While NCs were referred to as 'thin clients', the modern usage of this term generally refers to systems in which no local processing occurs. Examples of thin client hardware include VT100 and X terminals. The term 'thin client' also refers to applications, particularly on the world wide web, in which the server performs all processing, and the user interacts only with a HTML representation of the program via a web browser. The NC was distinct from what would today be referred to a thin client in that the processing was performed locally, using the NC's own hardware, with application and data storage performed via the network.

Whereas the dumb terminals (VT100, X) of yesteryear required both remote file server and remote central processing facilities, the NC promised to allow administrators to reduce costs while still retaining the low per-desktop support costs of centralised computing. In many universities and data centres, PCs are used in a similar configuration, with applications and email stored remotely but executed locally.

	Terminal	NC	PC
Local mass storage
Local general-purpose processing
I/O

History and NCs today

The failure of the NC to impact on the scale predicted by Larry Ellison may have been caused by a number of factors. Firstly, the idea could simply have been ahead of its time. At the NC's launch in 1996, the typical home Internet user was using only a dialup connection via a modem. The common 28.8 kbit/s speeds would simply not be sufficient for the delivery of executable content.

The world wide web itself was not considered mainstream until its breakout year in 1998. Prior to this, very few Internet service providers advertised in mainstream press (at least outside of the USA), and knowledge of the Internet and the web was limited. This could have held back uptake of what would be seen as a very niche device with no (then) obvious appeal.

As a result of the NC's perceived failure and the original low (sub-US$400) cost of the devices, NCs can still be purchased very cheaply from online auction sites such as eBay. In particular, Acorn NetStation and Sun JavaStation appliances can be found in as-new boxed condition for a fraction of the original price.

Ironically, these devices end up being used as the very 'dumb terminals' they were intended to replace, as the proprietary backend infrastructure is not readily available. 1990s era NCs are often network-booted into a minimal Unix with X, to serve as X terminal. While NC purists may consider this to be a suboptimal use of NC hardware, the NCs work well as terminals, and are considerably cheaper than purpose-built terminal hardware.

As of 2005, MIT has announced a project to create a sub-US$100 'laptop' for use in third-world countries. Details on MIT's project web site suggest that the device will operate on NC principles, supporting local processing but with minimal local storage. The laptop will be dependent upon network infrastructure, but will not require extensive centralised computation resources.

NC Standards

The NC standard required that all 'NC' appliances supported HTML, Java, HTTP, JPEG. Many NCs operated via protocols such as BOOTP, DHCP, RARP and NFS.

Both for Internet service provider-bound and LAN-based reference implementation NCs, a smartcard option was available. This allowed user authentication to be performed in a secure manner, with SSL providing transport security. The smartcard also provided minimal local storage for ISP dialup configuration settings. This configuration data was not required for LAN-based NC.

NC implementations

Acorn Computers

Oracle's initial reference implementation of the NC was created by Sophie Wilson of Acorn Computers, which later changed its name to Element 14 before being bought by Broadcom.

The NCOS used in this first implementation was based on RISC OS and ran on ARM hardware. The NetStation was available in two versions, one with a modem for home use via a television, and a version with an Ethernet card for use in businesses and schools with VGA monitors and an on-site BSD Unix fileserver based on RiscBSD, an early ARM port of NetBSD. Both versions were upgradable, as the modem and Ethernet cards were replaceable podules (Acorn-format Eurocards).

The second generation NCOS was no longer based on RISC OS, and instead consisted of NetBSD 1.2.1 code. Later NCs were produced based on the Intel Pentium architecture, although Acorn continued to produce ARM-based designs, including the StrongARM-based ConNCord.

NetProducts NetStation

The first generation NetStation design and the NetStation trademark was licensed to NChannel, which provided the consumer equipment and Internet service (with associated infrastructure) for the UK market. After a few months, NChannel split into two entities: NetChannel (which provided the Internet service) and NetProducts which provided the consumer hardware.

NetProducts started working with Acorn to develop a next-generation product, NetStation II and separately from Apple started developing an email-only set-top-box (the TVemail). NetProducts went into voluntary liquidation in 1998 before either project was completed.

Sun Microsystems JavaStation

Sun Microsystems developed the JavaStation, a JavaOS-based NC based on SPARC hardware, initially similar to Sun's range of Unix workstations.

RCA Network Computer

RCA created a Network Computer, but little is known about it.

IBM Network Station

IBM also created a number of NC appliances. As with the later reference design, the Network Station used a NetBSD-based NCOS booted over a LAN from an AS/400 or IBM PC server. The Network Station supported local execution of basic applications, such as a web browser and console. In addition, X capability was also implemented to allow both locally and remotely run applications to be used on the same machine. In practice, the lack of real applications meant that this was little more than a hardware X terminal.

The IBM Network Station was originally based on the PowerPC architecture, but the final few models used Intel Pentium processors.

Apple Interactive Television / Apple Set Top Box, Model# M4120

The Apple ITV is quite a mystery. An early prototype based on LC 475 hardware was demonstrated at MacWorld Expo Boston in 1995, but the final product never shipped and a great deal about the product, including the technical infrastructure that it was to operate on, remains unknown to the general public.

Later efforts at an Apple network computer evolved into the iMac.

Similar technology

Apple Computer has a technology called NetBoot that allows New World Macs to boot from a network. NetBoot is included as part of Mac OS X Server.

Many other Unix implementations support network booting and diskless operation. These standards were the basis for the original NC implementations. BOOTP, RARP, DHCP and NFS were the main network-end configuration protocols.

External links

An FAQ on the NC: http://www.faqs.org/faqs/network-computers/faq/
Contemporary article on the NC: http://www.byte.com/art/9704/sec6/art1.htm
No Network, No Demo; Oracle's NC Demo Dies Onstage: http://www.techweb.com/wire/news/1997/09/0924ellison.html
Contemporary press coverage of NC pricing: http://news.com.com/Oracle+down+to+brass+tacks+for+NC/2100-1001_3-243680.html
Acorn CoNCord release article: http://news.com.com/2100-1033-203957.html
A brief overview of the (IBM) Network Station: http://www.uwasa.fi/~f76998/netstation/overview/

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