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(This article was first published in the ICPUG
Journal SEPT / OCT 1989 issue.
Permission from Joe Griffin to republish on the Internet has been
received.)
JIFFYDOS - REVIEWED by Joe Griffin
Those of you who have read my Seven-and-a-Half Bits column in this issue
will have seen that I sing the praises of Creative Micro Designs ( of
Wilbaraham, Massachusetts). They have produced a fix ROM for the 1280
Desktop machines. Testing the ROM installed in my 128D showed that it is
compatible with all my software and does finally nail the side two BAM bug.
Hence it has become a standard fitting in my 128D. This ROM is not a
stand-alone item but is part of the JiffyDOS system.
JIFFYDOS is a speed enhancement system for the 64 and 128
with appropriate drives. Unlike other devices which wedge code into the
operating system, JiffyDOS replaces the ROM chips in both the kernal and
the drive, to give a fully compatible system. The system is available for
64, 64-C, SX-64, 128 (and 1280 portable) and the 128D desktop machines.
Disk drives covered include 1541, 1541-C, 1541-11, 1571 and 1581 plus a
number of third party drives.
The system comes as a pair of chips, one each for the
computer and drive. For the 128D and SX-64 the drive ROM is the one for the
installed drive but for the other machines the user specifies what drive
is required. The chips come with full fitting instructions and installation
in my 128D, including drilling a hole for the control switch, took about 15
minutes.
In use, the first thing I found with JiffyDOS is that
formatting of disks on the 1571 in 1541 mode is carried out at 1571 speed,
even when the system is not activated. With the Commodore ROM, formatting a
1541 disk look 73 seconds. With the JiffyDOS drive ROM installed, but not
the kernal, the time was down to 23 seconds.
On the 128, file save times, for both program and data
files, was reduced by 30% and the time to read a text file into
Superscript was reduced by about 10%.
40 column mode cannot use the fast 2MHz processor speed but use of the
JiffyDOS system allowed this mode to turn in file loading/saving times as
good as in 80 column mode. In 40 columns the reading time was reduced by
40% compared with the stock system. In native 128 mode, reading an entire
disk with Jim Butterfield's 'Disk Log' program showed a 30% gain in 80
column mode when JiffyDOS was activated. Load times for program files
seemed to be unaffected by the system, though the manual indicates that
there should be a noticeable improvement.
The biggest difference came when the drive was set in 1541
mode. Without JiffyDOS, the speeds were those of the sluggish 1541, but
enabling the system put the speed up to that of the 1571.
With the computer set in 64 mode, there were vast
improvements in disk access speed. The stock system limps along at 1541
speed, even if the drive has been forced into 1571 mode. Once JiffyDOS had
been enabled the drive, in 1541 mode, returned speeds equal to those from
the 1571 in 80 column 128 mode. If the drive was forced into 1571 mode (or
64 mode entered from 128 mode by 'G064') then the speeds reverted to those
of the 154l ! The manual warns of this.
As well as providing improved disk access, the system
includes a DOS wedge, which makes disk housekeeping a lot easier,
especially in 64 mode. The wedge allows the user to specify a drive number
to be accessed, so multiple drives can be used and it includes the ability
to list a program or text file to the screen, without disturbing the
current program.
The only disadvantage of using JiffyDOS is that when it is enabled, the
tape routines are not available. The space taken by these routines is used
for the fast access code. However, a switch is provided which allows
JiffyDOS to be disabled should the need arise.
In conclusion, the 80 column user will see faster file saving and faster
reading of sequential files. In 40 column mode all disk operations will be
about 30% quicker than with a stock system while in C-64 mode, a reduction
of about 50% can be expected. C-64 users and those with 1541 drives can
expect most benefit from this system. Anyone who has a metal cased 128D is
strongly urged to obtain at least the 1571D fix ROM and benefits will be
gained by obtaining the full JiffyDOS system.
At the start of this review I said that JiffyDOS has become
a fixture in my machine. Version 6 of JiffyDOS has now been released but I
have not yet received a copy, though it is expected at any time and I
anxiously await the arrival of both the new kernal and a ROM for my 1581.
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