ch01.htm

this describes managing multivendor networks

	Digital terminal line to penetrate deep into both the technical and end-user communities.
</UL>

<P>The following generations of products compose the fundamental line of Digital
video terminal (VT) devices:

<UL>
	<LI><I>VT50 Family.</I> This is the father of the VT line. Although not as capable
	as today's products, the VT52 implementation in particular is still widely emulated
	by PCs and terminals that require character-oriented access. Its sibling, the VT55,
	offered support for combined on-screen text and graphics.<BR>
	<BR>
	
	<LI><I>VT100 Family.</I> Introduced in 1978, the VT100 line offered improved speed
	and function over the initial VT50 models. Of significance was the VT100 line's support
	for both ANSI and VT52 compatabilities. The original VT100 sired the following models:<BR>
	<BR>
	
	<UL>
		<LI><I>VT101. </I>Became the new low-end product.<BR>
		<BR>
		
		<LI><I>VT102. </I>Offers advanced video options, including support for 132 columns
		by 24 lines.<BR>
		<BR>
		
		<LI><I>VT131</I>. Supports both conversational (character-oriented) and block mode
		(full-screen) transmission modes.<BR>
		<BR>
		
		<LI><I>VT125</I>. Combines text with bitmapped graphics capabilities. The VT125 includes
		implementation of Digital's Remote Graphics Instruction Set (ReGIS).<BR>
		<BR>
		
	</UL>
	<LI><I>VT200 Family.</I> One of the most important features of the VT200 family is
	the keyboard layout. While the VT100 had a separate (right-hand) numeric keypad,
	the VT200 added another keypad for editing (located between the typewriter keys and
	the numeric key-pad). Another significant change from the VT100 family was the introduction
	of a user-friendly on-screen menu to define the various set-up options (in contrast
	to the cryptic on-screen sequence used by the VT100). The VT200 family is composed
	of three major models:<BR>
	<BR>
	
	<UL>
		<LI><I>VT220. </I>A standard monochrome text-only video terminal.<BR>
		<BR>
		
		<LI><I>VT240. </I>Supports text and ReGIS monochrome graphics. It is composed of
		a keyboard, monitor, and a system unit box.<BR>
		<BR>
		
		<LI><I>VT241. </I>A color implementation of the VT240.<BR>
		<BR>
		
		<LI><I>VT300 Family.</I> The VT300 line offersincreased performance and ergonomics
		(reduced glare and tilt/swivel base) over the VT200 line. The VT300 line includes:
		<LI><I>VT320. </I>The entry-level monochrome text video terminal.<BR>
		<BR>
		
		<LI><I>VT330. </I>The monochrome graphics (ReGIS) replacement for the VT240. The
		design of the VT330 eliminated the need for a separate system unit. Also note- worthy
		is the VT330's dual-session (dual-port) capability and improved graphics resolution.
		An improved, higher performance model of the VT330 was released as the VT330+.<BR>
		<BR>
		
		<LI><I>VT340</I>. A color implementation of the VT330. A high-performance version
		of the VT340 was released as the VT340+.<BR>
		<BR>
		
	</UL>
	<LI><I>VT400 Family.</I> The VT400 family was introduced in 1990 as the planned replacement
	for the three-year-old VT300 line. The VT400 line includes improved resident fonts
	that enable it to display 24, 36, or 48 lines of text per display screen. The VT400
	line was introduced with one model, the VT420--a monochrome text terminal. The VT420
	supports dual ports (for dual sessions) and provides split-screen and cut-and-paste
	functions for managing both sessions.<BR>
	<BR>
	
	<LI><I>VT1000 Family.</I> The VT1000 is a specialized graphics workstation supporting
	icons and multiple windows in accordance with the X Window standard. The highly intelligent
	VT1000 also provides VT320 terminal emulation and support for both the Local Area
	Transport (LAT) protocol, Transmission Control Protocol/Internet Protocol (TCP/IP),
	and the standard X Window System protocol.
</UL>

<P>In most cases, Digital terminals transmit characters as they are pressed on the
keyboard. Issues such as buffering and transmission optimization are handled by the
computer system or by the devices between the terminal and the computer system. These
considerations will be discussed later in this chapter.
<H3><A NAME="Heading4"></A><FONT COLOR="#000077">PCs</FONT></H3>
<P>The terms <I>personal computer</I> and <I>Digital Equipment Corporation </I>are
not as synonymous as one might expect. It is not that Digital has been unable to
apply its innovative talents in this arena, or that the resulting products did not
come to market. The real problem rests with timing. Before IBM's release of the first
PC, Digital had also been working on a small, personal microcomputer. At that time
there was no single dominant hardware architecture or dominant operating system on
the market (although the Control Program/Microprocessor [CP/M] was doing well at
that time).</P>
<P>When IBM released the first PC in 1981 (and subsequently set the standards for
today's market), Digital redoubled its efforts to get its own products to market.
Digital produced not one but three possible contenders for the low-end market. Each
had its own distinct advantages and disadvantages, and each was given an opportunity
to prove itself.</P>
<P>The three products that resulted were the DEC Rainbow, the DECmate, and the Professional
300. Of these three, the DEC Rainbow was the only product that came close to being
a clone of the IBM PC; the Rainbow ran Microsoft's MS-DOS operating system but did
not feature the Basic Input/Output System (BIOS) and hardware-level compatibility
with the IBM machines.</P>
<P>In contrast, the DECmate and the Professional 300 lines were corporate-oriented
computers. For example, the DECmate featured sophisticated word-processing capabilities
and could be networked easily with Digital's larger machines. The Professional 300,
on the other hand, was intended to be a desktop version of the Digital's PDP computer.</P>
<P>None of these three products have any inherent, glaring faults, but all three
were released in the shadow of the IBM PC (and the emerging clone market), which
fell on them like a wet wool blanket. Although it is certainly unfair to call any
of the products a market failure, none achieved the celebrity status earned by the
IBM PC. Digital's resigned mindset was further evidenced by the release of the VAXmate,
a follow-up product to the IBM PC/AT. Based on the same Intel 80286 microprocessor
chip as the IBM AT, the VAXmate had limited expansion capabilities and was marketed
only to existing Digital customers.</P>
<P>At the end of the 1980s, Digital was ready to take another chance on the IBM PC-compatible
market. This time, however, it turned to Tandy Corporation (Radio Shack; Fort Worth,
Texas) to manufacture a line of PC-compatible products for Digital. The resulting
products were the DECstation 200, DECstation 300, and DECstation 400 lines--based
on the Intel 80286, 80386, and 80486 processors, respectively. Although Digital downplayed
the fact that it had out-sourced the product to Tandy, this fact was not lost on
the market.</P>
<P>Finally, in 1990, Digital released the applicationDEC 433MP, a multi-user UNIX
system based on the Intel 80486 microprocessor. This product was targeted at the
small-business market and features support for multiple 486 processors and connectivity
for up to 96 concurrent users. Its roots in PC and Personal System/2 (PS/2) technology
are evident by its support for either the Extended Industry Standard Architecture
(EISA) or Micro Channel Architecture (MCA) bus. If nothing else, the 433MP represents
an interesting convergence of PC, engineering workstation, and minicomputer technologies.</P>
<P>Digital's latest innovation, the Digital Personal Workstation, is designed around
a processor-independent architecture, and offers the user a choice between Pentium,
Pentium Pro, or Alpha processors. Users can move from Intel to Alpha with the change
of a single card. Both processors are optimized to run Windows NT, and can be used
to run many of the high-end applications, such as CAD or GIS, that had been limited
to higher-end workstation products. It offers PCI or ISA Ethernet or token ring options
for networking. The Celebris XL is based on Intel technology and features either
single 100, 120, or 133 MHz; or dual 100 or 133 MHz Pentium processors. The Alpha
XL runs 233 MHz and 266 MHz implementations of the Alpha 21064 processor. Several
native Windows NT applications have been ported to the Alpha system as a result of
an alliance between Digital and Microsoft.
<H3><A NAME="Heading5"></A><FONT COLOR="#000077">Engineering Workstations</FONT></H3>
<P>Digital's original response to the engineering workstation market was to couple
high-resolution displays with various VAX processors. Capable of running either the
VMS operating system or ULTRIX (Digital's implementation of UNIX), the product line
was termed the <I>VAXstation.</I></P>
<P>In general, as the capabilities of the mainstream VAX models grew, so did those
of the VAX-stations. The VAXstation 100/500 line introduced in the early 1980s was
replaced by the VAXstation II in 1985, a line that included a model with an independent
graphics coprocessor. On the heels of the VAXstation II came the VAXstation 2000-7000,
released in 1987 and 1988.</P>
<P>The VAX 7000 was designed as a high-performance system, suitable for high-volume
transactions or distributed networks. Many mainframe-based applications could run
on the VAX 7000, making it usable as a backbone platform for supporting business-critical
applications. The VAX 7000, which was expandable to six CPUs, was built on Digital's
CMOS technology and ran the OpenVMS operating system.</P>
<P>In 1989, Digital revamped its product line and stirred some new ingredients into
the mix. The first ingredient was the use of a RISC architecture for some of the
machines. Another was that the basic RISC processor used by Digital was, in fact,
manufactured by MIPS Computer Systems, a third party supplier. Finally, these new
RISC-oriented machines could run only ULTRIX (and thus were shunned from the VAX
community).</P>
<P>Presumably to reduce confusion between the VAX-based and RISC-based products,
Digital named the new line <I>DECstations</I> (a named shared by Digital's MS-DOS
computers). Digital targeted this new lineup as a sweeping, low-end desktop blitz
and paraded it in front of the public.</P>
<P>The product lineups consisted of the VAXstation 3000 Series (based on Digital
complementary metal oxide conductor, or <I>CMOS,</I> VAX processor technology); the
DECstation 5000 Series (based on the MIPS RISC architecture); and the DECstation
200, 300, and 400 Series (based on the Intel 80286, 80386, and 80486 microprocessors).
While the low-end, PC-oriented DECstations were not presented as heirs to the engineering
workstation throne, the association (by name alone) of the DECstation 3000 Series
with these units raised both eyebrows and confusion.</P>
<P>The AlphaStation 255 and 500 families of UNIX and Windows NT workstations are
the latest additions to Digital's line of midrange workstations. Digital's AlphaStations
support Digital's new 64-bit operating systems (Digital UNIX and OpenVMS), as well
as Windows NT.</P>
<P>The 500 supports dual-fast and wide SCSI-2 channels, Ethernet and Fast Ethernet,
and can accommodate up to 512M of RAM. All products in the AlphaStation line include
multimedia capabilities.</P>
<P>The PowerStorm PCI-based workstation graphics option is available for all Digital
workstations. PowerStorm delivers superior graphics performance, using the common
OpenGL API. PowerStorm was designed for 2-D and advanced 3-D applications that require
high performance, such as motion and texture mapping.</P>
<P>Digital's RISC-based AlphaStations offer superior performance for applications
such as modeling, imaging, animation or videoconferencing. The new 64-bit architecture
can directly address up to 1G of real memory, making it easier to handle very large
files without disk-swapping. The newest AlphaStations run the 64-bit RISC Alpha 21164
microprocessor, at speeds up to 300 MHz. Like the other Digital products running
Alpha technology, it can run UNIX, OpenVMS or Windows NT.</P>
<P>The AlphaStation 250 is well-suited to mechanical or electrical CAD applications,