DoubleView is a ROM-based piece of software from Tubelink designed to work with Acorn's View word processor, and providing both additional features such as split-screen dual-file editing, and enhanced versions of existing ones. The software is in the form of two 16K ROMs, or in ROM image format for loading into sideways RAM. It is accompanied by a 32 page manual. You must also have the View word processor installed in your machine, and version 3.0 or later at that.

DoubleView also needs one 16K bank of sideways RAM for use as workspace, and the manual also recommends the use of shadow RAM if you want to be able to store reasonable quantities of text in memory.

Once installed on your system, DoubleView is called up with *DBVIEW. This takes you directly into View's edit mode, but with an additional status line (in inverse video) at the foot of the screen. This information, which is continually updated, shows the name of the current document and printer driver. It also shows the number of free bytes, which markers are set,and your position in the current document as a percentage. 0% is displayed when the cursor is at the start of the document, 100% when at the end and other values appropriately in between.

One point to note is that DoubleView will only work in modes 0 and 3 (most dedicated View users seem to prefer mode 3), but for extensive use in these modes a high resolution monochrome monitor is much kinder on the eyes than the typical medium resolution colour monitor. And in these modes, DoubleView can also provide a 106 column screen as an alternative to the more usual 80 columns if required.

Within edit mode, text may be entered and processed as usual with View - nothing has been changed in this respect. However, a range of Control key functions has been added which implement a good many of DoubleView's extra features. Ctrl-f9 provides a Delete Word function, while Ctrl-T and Ctrl-E will move the cursor to the top or bottom of the current screen.

One of the most important improvements is the option to handle two separate documents together, which gives the package its name. Once the first document has been loaded, Ctrl-X will toggle the alternative screen window, and a second text file may then be loaded. In addition, Ctrl-F also allows the user to switch between having just one editing window and two windows on the screen. Thus parts of both documents may be displayed simultaneously, and Ctrl-X then toggles between the two screens. Ctrl-W allows the relative sizes of the two windows to be adjusted, while Ctrl-U and Ctrl-D allow the text in the other window (i.e. not the one in which you are currently working) to be scrolled up and down. This saves unnecessary toggling between windows.

Another feature implemented via Control keys is a clipboard. The clipboard is a file on disc created and maintained by DoubleView. Any piece of text delineated by markers may be copied (Ctrl-L) or cut (Ctrl-K) to the clipboard, and the contents of the clipboard may be pasted (Ctrl-P) at the current cursor position.

Unlike View, DoubleView allows the user to specify a wealth of start-up options and the names of up to two files for editing when called with the *DBVIEW command. This information is supplied as a set of parameters following the command itself.

The choice is quite comprehensive, and as such it would probably make more sense to put a command into a !BOOT file. However, DoubleView addresses this problem too, and a single 'O' option may be used to specify the name of an options file. Using this facility you can select a one or two window screen on entry, screen mode (0 or 3), and the colours of text and background. Other options allow the user to determine the size of the upper window (and thus also the lower one), choice of normal or wide screen (106 columns), and the cursor flash rate.

There are some more interesting options too. Disc buffering, if selected, allows more memory per document when editing two documents together by saving the non-active document when a switch is made from one window to the other. Disc buffering can use floppy disc (but this is quite slow), hard disc or a RAM disc if available. The result is that even when editing two documents, each document can use all available memory. The 'Recovery Files' option implements a system whereby any document being edited is saved at regular intervals (determined by the user), for recovery in the event of some catastrophe. With dual file editing, only the active file is backed up in this way as the non-active file is saved anyway.

Another important option provides a 'Multi-File' facility. A master file may be set up with the names of View files. If the master file is specified on entry, the first View file named is loaded. Moving to the end of this file and pressing Ctrl-Cursor Down automatically saves the current document and loads in the next. You can also move back to a previous document in the same way. As a means of allowing much larger files to be edited this is a step in the right direction, but it would have been really good if this had been made totally transparent to the user.

Pressing Escape in edit mode no longer takes you into View's normal command mode, but into DoubleView's main menu. This provides ten menu options replacing and supplementing View's own commands. These options include:

1. Word Processor Commands to deal with View commands like Search, Replace, Fold etc. 2. Multi-File Documents to create and edit the master files referred to before. 3. Options Adjustment to set or change start-up options from within DoubleView.

There is also a facility to enter ViewSheet (Acorn's spreadsheet equivalent of View), and from within that package to use two further Control keys to return to DoubleView or save a spreadsheet to the clipboard. Tubelink promises a full DoubleSheet for the future.

I have mixed feelings about the usefulness of DoubleView. As a longstanding proponent of View for word processing, I welcome any product which will enhance View's editing environment. The dual-file editing facility and split screen, together with the clipboard, are very welcome, though it would have been useful to be able to view the contents of the clipboard without having to load them into one of the two screen windows.

The automatic back-up at regular intervals would certainly have been a life-saver for me in the past, and I suspect for many others. But I am less sure about the multi-file facility for the reason stated.

The start-up functions are attractive, and the 106 column screen, on a high resolution mono monitor, is eminently readable for those wider documents. The manual explains everything well, though the order of the contents seems a little haphazard. And all Control key functions and start-up options are listed for reference at the back.

Provided you have both sideways and shadow RAM, then at just under £40 the price of this product seems reasonable. If you edit many long text files, and frequently need to cut and paste between documents then I am sure that you will rapidly find DoubleView to be invaluable.

Product: DoubleView
Supplier: Tubelink PO Box 641, London NW9 8TF. Tel: 01-205 9393
Price: £39.95 (5.25" or 3.5" disc), £49.95 (two 16K ROMs)