here is a list of changes i made since using the sb180.

1. i re-designed the board to bring out the full potential of the hitach part.
   my new board utilizes a fully buffered buss, with enough drive ability
   to support 2 meg worth of ram.
   this ram is configured as one "fixed" block of 256k with seven blocks
   of mapped 256kb. I did it like this to allow easy control by a ram disc
   driver. the code for implementing this consists of very minor mods
   to Joe Wright's bios code. by the way, it is zero-wait state memory and
   removing the one hardware-forced wait in the SB180 yields a %25 speed
   improvement. I also made use of all the available 232 terms so that
   DCD and CTS arent sharing chips. oh yes, the board is one inch wider
   then the original sb180 pca and only the first 512kb is on the board.
   those new 256k dram in "zip packs" would allow 1 meg on the pca.

2. on screen clock, updated every sec. does not interfere with graphics/
   windowing software. this was a pain to set up and hogged up some space! 
3. on screen modem status. (i often forgot to disc. the modem, my wife
   didnt like it when the modem answered the in-law's calls).

Tcap support for the "host message line" provided by terminals would make
 the implementation of these features (2,3) terminal independant. Oh well.


4. Separate recv,send,disc, status test, port-setup, and terminal routines.
   no dialer cause i dont have an autodialer. Standard Christenson
   protocol (CRC+CSUM) supported. Interrupt driven recv buffering.
5. mappable rom space. boot rom mapped out after boot load (even .5meg
   system has 448kb ram disc). secondary romspace mappable on 16k bounds
   throughout first 128k. rom is directly accessable as disk file.
6. recorder iop implemented. I just couldnt see paying $40.
   the actual code for this is already on this system as DISCIOP.Z80.
   you can "plug this code segment into EDI CRAMP's sysiop and your all set!
7. hardware rtc (nat 58274) utilized. TIMESTMP program used to timestamp
   source files with yr/mo/da  hh/mm/ss am/pm rev. (battery backed too)
8. modified config to allow parity control on async ports.
9. modified bios to support illegal op trap.
10.added parallel modem/console for remote use
11.warm boots are now done out of ram disc. this costs 2k and another
   revision to mdsk.*****this mod is really the hot setup!*****************
12. i also altered the "break fix" so the console buffer is flushed. ever
   get stuck with a buffer full of commands? with this they can be flushed. 
.
.
along the line ive had to rewrite or modify:
config
sysgen
bios, lots of changes, lots. I dont, and never will, use 8 inch discs
 so i deleted the code supporting them. there is also other extraneous
 code that serves no purpose. the space gained made room for the clock code
 and all the other changes i had to make. realize that you dont HAVE to
 strip this code to set up the warmboot mod, but to get the on screen clock
 youll need some space.
fcp (due to ~error in test polarity)
rcp (needed REG)
iop (to support TANDEM 6530 and recorder)
ports.lib
mdsk, to support the added ram space and warm booting from ramdisc
hboot, to support loading into different ram space
the monitor rom, again to support loading the system into a diff area.
time, it still does all it did but now is used with the rtc chip. the
 main use it gets is setting the software clock from the RTC chip at boot.
fvc, which now can learn various formats, perform real diagnostic tests,
     assist in alignment (using an alignment disc), and generally
     do a few more items. also i fixed the problem with the copy routine.
.
most were only small mods, and some were substantial changes.
.
ive replaced my dos once and my assembler 3 times.
its getting better all the time.
.
for those of you who have implemented the mods to bring the system up to 
512 kb i would reccomend setting up the ramdisc as drive A and putting a
copy of the CCP immediatly after the directory space. setting one more
bit in the initial allocation vector will protect the 2k CCP from ERA's and
cleandir.
the code in wboot is then modified to dma the CCP at warm boot. this
saves a lot of time. warm boots are instantaneous! the startup alias is
modified to establish B15: as the root directory. and mdsk is also 
modified to copy the real ccp into the ramdisk at coldstart. in this setup
ramdisc is A, physical drive 0 is B and so on.

i dont know if any of you out there will be interested in any of the mods ive
made, but if you would like to talk to me about them, or maybe tell me about
some of the mods youve done, i can be reached at 916 925 6089.

maybe naog would be interested in some of this? i am not willing to pay 35$
for access to liliput z-node though. it aggravates me to spend 15 bucks
for a news letter then have to pay more to get on a bbs to share with fellow
members. any comments about this?



jeff herr, sacto,ca.

r then have to pay more to get on a bbs to share with fellow
members. any com