Numeric Co-processors

If you make extensive use of applications that are concerned mainly with calculation then a numeric co-processor is essential. In this chapter we examine which co-processor is best and which application really benefit from one.

We have encountered the idea of a co-processors of a number of types in earlier chapters of this book. But historically the numeric co-processor was the earliest important and common example of a co-processor. A numeric co-processor takes over from the main processor whenever an arithmetic operation is needed. To be strictly accurate, numeric co-processors generally only take over when a floating point arithmetic operation is need. A floating point operation can be thought of as one that involves fractional numbers or results-but this isn’t entirely true because there is a way of handling fractional numbers that isn’t based on floating point numbers, called fixed point arithmetic. What all of this means to the user is that a numeric co-processor really only helps when you are doing arithmetic that involves something other than whole numbers, and usually only when multiplication, division or some complicated trigonometric or transcendental function is part of the calculation.

Watch the video down below.

Notice that this implies not only the use of an EISA/MCA bus machine but an EISA/MCA disk controller and network adapter cards. Of course, moving to an EISA/MCA based machine will not solve a performance problem caused by workstation overloading the capacity of the network itself, or anything else not related to the movement of data within the server. 

Landscape or Portrait

The one problem with  1024 x 1024 resolution colours  monitors and graphics  adapters  is their cost. A 1024 x 768 Super VGA display may not seem that for away from that desired resolution and it  much cheaper. The trouble is that  for an A4 page  the aspect  ratio is wrong – that is a Super VGA monitor is a landscape  monitor with 1024 pixels across the  screen. This makes it suitable  for full page  illustration  work or even for  viewing spreadsheets, but it isn’t much good for DTP work which nearly  always works with pages that are  longer than they are  wide.  There are a number of  solutions to  this problem. The first is the  obvious  hardware solution of turning the  monitor one its side to converting it to a portrait  monitors. This isn’t  quite as easy as a  it sounds because  you not only need to  alter the way  that the monitor is  mounted, but you also need special  video drivers   that turn the image through  the same right  angle! There are  a number of VGA  adapter cards that  support a rotated  display,  the best known example of which  is the Radius  Pivot.  This consists  of a specially designed Super VGA  card and a  monitor which  pivots. The  driver can detect  the orientation of the monitor  and so automatically switch  the  display from landscape to portrait interactively. This is an ideal display if you need  to work in   both landscape  and portrait  mode.

As alternative  software-only  solution is  to use a driver that creates a language  virtual screen using RAM. The actual  video display is then  used as a  window into  this larger display.  The advantage of this is that  the driver can also automatically  detect when the  mouse pointer is  about to be moved  off the edge of  the screen and   can move the  window to  show another  portion of the screen. The best known examples  of this approach  are SoftKicker for Venture GEM and  more Windows which work with any  Windows 3 application. These products  only work with  standard  and not Super VGA  but they still do  a good job of simulating  a full A4 display in monochrome and in colours.

Does the video bus matter?

Many graphics boards are available in MCA (both 16 and 32 bit), ISA (both 8 and 16 bit) and EISA, and this raises the question of the  effect the bus standard has on graphics performance. This question is a very difficult one.  On the face of it,  a graphics board requires a large amount of data to be transferred  at high speed and   therefore a 32-bit MCA or EISA  bus 

If you do need the increased resolution, i.e. beyond 1024 x 768 in 256 colourss for applications such as  DTP, CAD or  any graphics –dependent task, then your choice is  between an  intelligent controller or a specialized A4/A3 monitor. Which you chose  depends on your budget and you need for  colours.

Find many DTP and some CAD         applications colours is  a luxury and so an A4/A3 monitor is cheaper and more suitable. If you need  24-bit colours then an EISA or MCA based machine is preferable.

Exactly which model of graphics adapter you should  choose  will obviously  depends on how much you can  afford to spend,  but the most  crucial issue is the  existence of a working and  up-to-date  driver for the  applications that you  want to use.  Without a software driver  all of the super  features, speed and excellence of a graphics board are pointless because you cant use them.