Diversi-DOS. (software for disk operating system for Apple) (evaluation) Robin Raygor.
Many of us have been painfully aware of the inefficiencies in Apple's DOS 3.3 for some time. Many very useful programs from Apple Writer to VisiCalc have seen us sitting idle (through no fault of their own) while we waited for information to be written to or read from disk.
We have watched with some anticipation, the development of various attempts to speed up DOS. These attempts have so far consisted primarily of partial fixes which speed up some DOS operations but not others. Enter Bill Basham's Diversi-DOS.
As far as I can tell, there is no major disk operation that this system does not speed up. I tested it against Apple DOS, and although the differences were not quite as great as those listed in DSR's advertising, they were still enough to make me sit up and take notice.
I used a 139-sector binary program to check BLOAD and BRUN times. For the rest of the times I used a 66-sector Applesoft program I wrote to manage multiple choice and true-false test items. This program uses a random access text file containing 150 test items each of which has a record length of 500 characters. The total length of the file is 230 sectors. As you can see in Table 1, Diversi-DOS read the file in 55.2 seconds, close to half the time it took Apple DOS. This was without using the call to an intrinsic subroutine which sets the record parameter and presumably allows you to read and write random access files even faster than this.
Some of the file operations were so fast I thought something was wrong. The most dramatic differences involved handling binary files. Anyone who has spent much time waiting for long binary game programs to load can probably get fairly excited about an operating system that handles binary files more than four times as fast as Apple DOS.
The spectacular performance of this product is almost eclipsed by DSR's unique marketing approach. When you boot the master disk you are confronted with the novel message Please copy this disk and give it to everyone you know. This rather startling proclamation is followed by nine exclamation points to let you know they are serious.
The text goes on to explain that it is legal to copy the disk but to use Diversi-DOS requires that $25 be sent directly to DSR.
In a time of escalating piracy/ protection techniques it is quite refreshing to see this kind of trust on the part of a software vendor. DSR claims that this method cuts distribution costs by over fifty percent, and, to their great satisfaction, people are actually sending in the money.
As if the hot operating system weren't enough, DSR offers some very attractive accessories with Diversi-DOS. A typeahead buffer allows you to type at full speed, even when the disk is spinning, and not lose any characters. This is extremely handy for dreary multiple file operations like renaming all the files on a disk.
An optional print buffer does the same thing on the output side by using the disk as a buffer to store text on its way to the printer. Also included is a DOS mover option which moves Diversi-DOS into a RAM card if available.
Although Diversi-DOS comes with no manual in the traditional sense, ample documentation is contained in the menu and the extensive instructions on the disk. One menu option allows dumping the instructions to a printer. The instructions can also be converted to a standard text file so they can be edited and printed out in any format you like. The instructions are clear and accurate and go far beyond just explaining how to work Diversi-DOS.
Included are a custom printer driver for word processors, instructions for making Diversi-DOS work with Fid, Renumber, DOS Toolkit, 40-track drives, hard disks, etc. The instructions also cover setting up the new RESET vectors, installing Diversi-DOS on existing disks, and creating data disks with 32 extra sectors.
One menu option even finds the greeting program on protected disks and runs it for you. This works on any program using a normal DOS format and allows you to use Diversi-DOS with many commercial programs including Screenwriter II and many game programs.
You have to be fairly picky to find fault with Diversi-DOS. I have tried everything I can think of to do with it, and it has performed flawlessly. The only drawback of any kind I could find is the lack of standard DOS error messages.
Many of the high speed operating systems for the Apple that are now becoming available have made room for their extra goodies by giving up the INIT command. Diversi-DOS supports all normal DOS commands by giving up the error messages. Instead, errors are reported by number.
Several other drawbacks surface when you use some of the accessory options that come on the Diversi-DOS master disk. The type-ahead buffer makes it impossible to PEEK at the keyboard strobe in the normal way to test for a keypress or tell the ASCII value of the key, although GET and INPUT work normally.
The print buffer which uses the disk for spooling also has problems. It disables the INIT and CHAIN commands and eliminates the functions of special printer cards, although in fairness, it is hard to imagine using these during spooling.
Not only are these drawbacks fairly minor, they can be avoided if necessary just by not using these options. Actually, the most serious drawback of Diversi-DOS is that it makes you impatient when operating the few programs that won't run under it.
Diversi-DOS really works. Rarely have I been this satisfied with a software product. Performance, documentation, and support are all superb. The author himself is available by phone every day from 3:00 to 5:00 p.m. to answer questions of registered users.
It seems likely that in the future software will come with Diversi-DOS or some similar fast operating system. Until then Diversi-DOS will be a valuable tool for anyone who has better things to do than sit and wait for the little red light to go out.
Products: DSR Diversi-DOS (computer program)