Commodore computer systems have always had bugs and quirks of varying severity. Some of the quirks may affect the operation when THE SERVANT is in charge of operations. Several known bugs has been circumvented in the design of THE SERVANT, but then there are some that can't be patched over. Below you'll find a list of the bugs and quirks known by the author that you may encounter.
ALL DISK DRIVES:
When you attempt to exceed the number of files permitted, odd things sometimes happens. The problem is worst on the 1571 (and possibly the 1541). Space is allocated for the new file while there is no room for the file name in the directory. The bug will especially affect the file copier. If you see the error message "disk full", you should validate the disk to put things right again. It should be noted that you won't encounter the disk full error if the file copier runs out of disk space (not exceeding the maximum number of files). A safeguard system prevents that. So far, I have not found a way to circumvent the problems that occur when you try to save too many files. So for the time being, validate the disk after a disk full error.
1571 DISK DRIVE:
The bugs apply to the 128D portable (128D with cooling fan & carrying handle), and the stand-alone 1571. However, upgrade ROM's has been released by Commodore to fix all problems. The Commodore part number of this ROM is 310654-05. You can get yourself the fix ROM by sending an 27256 EPROM along with the same turnaround fee and shipping charge that applies for SERVANT EPROMs. An even better alternative is JiffyDos, which further enhances the performance of your system (Please refer to appendix F).
Problems that may occur using "old-ROM" 1571's with THE SERVANT:
1) Random "device not present" errors. THE SERVANT may give up and make a bell tone on the Main Menu or aborting by displaying "I/O error" in the Disk Tools section.
2) Sequential file corruption. When a sequential file use blocks on both sides of the disk, it will sometimes get corrupted. Affects the File Copier.
3) The drive can't burst load "locked" files. Affects several SERVANT features.
4) Several bugs affects the speed of operations. The disk drive goes click-click-click for a very long time trying to recognize some disks, and the drive is very slow at writing data to the back side of the disk.
A public domain program exist named "1571.diag" which will check your drive to establish which type of ROM it contains.
1581 DISK DRIVE:
Three faults are known to the author:
1) At rare occasions, a disk may become severely corrupted. This is due to the WD1770-00 disk controller chip used in the original 1581's. This controller was later replaced by a WD1772-00 chip which solved that problem. It is not easy to replace the chip if you have the "wrong" one, because it is soldered in place. If you change chips, you may also short jumper J1 with a 47 ohm resistor. Although this is not essential, it will allow the drive to use the 6 ms step rate.
2) When creating a sub-sub directory (one subdirectory inside another subdirectory), the parent directory would sometimes be erased when the sub-sub directory was supposed to be formatted. In the design of THE SERVANT, an attempt has been made to patch up the problem, but I haven't been able to verify if it really fixes the problem. Please report if you run into trouble using THE SERVANT's partition creator making sub-sub directories.
3) Some 1581s has a poor solder joint on the motherboard. This joint is on pin 10 on device U10. It causes occasional "device not present" errors. THE SERVANT may give up and make a bell tone on the Main Menu or aborting by displaying "I/O error" in the Disk Tools section.
A program exists in the public domain called "1581.diag". It will identify the controller chip and the jumper J1, but not the poor solder joint.
1541 FORMATTED DISKS:
Some disks formatted by old 1541s or compatible disk drives seem to malfunction when read using a 1571 in 1571 mode. The disk seems to spin forever. This also happens with some older C64 commercial programs. The drive will recognize the disk if its left alone for a while though, and the delay may repeat every time the disk is read. The delay can be eliminated by switching your 1571 to 1541 mode.
From V4.84 and up, Call Exrom will work with the ROM chip called KeyDos. This didn't work before due to the inferior method used by KD to sense in which memory bank it is located. Not a TS bug, but a workaround has been employed which will ensure compatibility. However, the SYS address provided by KD at power-up to invoke it will not work. This is not a big problem, because you can use Call Exrom while holding down ALT, and KD will install gracefully.
The RAMlink (and probably RAMdrive) from Creative Micro Designs don't work well together with THE SERVANT nor any other function ROM chip. This is a problem inherent to the RAMlink hardware. However, THE SERVANT will work smoothly if RAMlink is switched off.
