Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!mit-eddie!killer!jolnet!dattier
From: dattier@jolnet.ORPK.IL.US (David Tamkin)
Newsgroups: comp.sys.cbm
Subject: 1541 speed-up command (Was turbodisks)
Summary: uj is the cold restart; it's ui-
Keywords: built-in faster serial communications for C-64 and 1541
Message-ID: <165@jolnet.ORPK.IL.US>
Date: 17 Feb 89 02:44:27 GMT
References: <8902130828.AA09474@MATH.Tau.Ac.IL> <2719@nunki.usc.edu>
Reply-To: dattier@jolnet.ORPK.IL.US (David Tamkin)
Organization: Jolnet, Public Access Unix, Orland Park (Joliet), Illinois
Lines: 23

In <2719@nunki.usc.edu> Alexander Liu wrote:

| One simple and unsophisticated (therefore, not that dramatic) approach
| to the speed-up problem is by using the 1541 fast mode.  I remember
| that the VIC-20 could make serial transfers 25% faster than the C-64,
| that's why C-64's had such a hard time reading the old 1540 drives.
| People who had VIC-20's could take advantage of this extra speed by
| sending the user command 'uj' to the disk (I am not 100% percent sure
| about this, I don't have my Disk Manual handy, but I think is fairly
| common thing)

uj is the DOS command to do a cold restart!  The one to speed up to 1540
compatibility is ui-.  ui+ slows it back down to 1541 speed for a C-64 with
its screen on.  (Mr. Liu remembered right that the C-64 can handle 1540
speed when its screen is blanked.)

Yes, I typed it correctly.  ui- to speed it up and ui+ to slow it down; you
may find the sign assignment counter-intuitive.

David W. Tamkin   POB 567542   Norridge IL  60656-7542 | 12 Adar Rishon 5749
dattier@jolnet.orpk.il.us    Jolnet Public Access Unix |   GEnie: D.W.TAMKIN
...!killer!jolnet!dattier        Orland Park, Illinois |     CIS: 73720,1570
Anyone on Jolnet who agrees with me is welcome to speak up on his or her own.