File:	CHARM::[LOGG.AMS]DNL.DOC
Date:	12/5/86


	The AMS fast download has been upgraded.  The changes are shown below.
Dave Shepperd will soon release a new DOWND which pass the symbol table to the
AMS as TEKHEX records.  This means one download will load the symbols and data.
	1. The AMS will now print any characters that are not part of a TEKHEX
	   or LDA record.  For example, if you started the download (pressed
	   ) before the LLF finished, then any LLF messages will be
	   displayed.  In addition, the sentinel "%" for the TEKHEX record will
	   be displayed at the beginning of each record.
	2. The AMS will now count the number of "." and generate a  when
	   the count exceeds 80.  The terminal no longer need be set on WRAP.

	In case you missed all the information on the fast downloader, here it 
is again.  There is no need to give up compatibility with old HEX files.  The 
new downloader will support extended TEKHEX, LDA and SYM files.  To get the new 
downloader do the following:
	1. Burn 2 27128-3 EPROMs from the file CHARM::[LOGG.AMS]U55U56D128.LDA
	   starting at 4000 and ending at BFFF.  Label them LOGG-U55 and
	   LOGG-U56 with the current date.  Please label the outside of the
	   AMS so that we do not send the AMS out for service with these 
	   EPROMs.  
	2. Replace the new U55 and U56 EPROMs with the ones in the AMS.  They
	   can be found on the PCB connected to the ribbon cable.  On power
	   up you will notice that there are CRC errors.  Please ignore these.
	   When I know how to CRC the EPROMs I will release a new version.
	   The current version has a CRC value of 273D.
	3. In your LOGIN.COM file define the symbol DNL.  Please see the DOWND
	   documentation if you need more information.  For example, it is
	   possible to tell DOWND to download several files at once.  More
	   importantly one can tell DOWND not to load all the uninitialized
	   data by specifying the starting and ending addresses.
		DNL :== MCR DOWND /DELAY=0 /RECORD=250 /ADD=start:end
	4. To use the new downloader, perform the following steps.  The AMS will
	   display a "." for each record read successfully.  The letter "X"
	   will be displayed when an transmission error occurs.  But don't 
	   worry because the downloader will ask the VAX to retransmit the last 
	   record.  A sample download is:
		>DNL				type this on the AMS as usual
		$ DNL filename.xxx	download filename.xxx
		....................		"." for each record read
		>				successful completion


	If there are any problems report them to me at x1732 or via VAXMAIL at
CHARM::LOGG and I will try to correct them immediately.  If you have other 
ideas let me know so that I can try them out or document them here in this 
file.  For those of you that would like to improve on the download time even 
further.  The following can be done:
	1. To speed up communication to the VAX, have the Systems Group set the 
	   terminal to 8 bit NOPARITY.  It will also be necessary to change the
	   AMS too by typing "SET #12,0", "SET #22,0", and "SAV".  This will 
	   reduce downloading by approximately 1/11 (from 11 bits per character 
	   to 10 bits). 
	2. As a last resort, you can break the download data into several 
	   sections and load them separately.  This is only helpful if a small
	   number of these sections are being modified at any one time.


	The current performance of the new downloader is shown in the following
table.  Please note that your mileage may vary.  For your information, it takes
the VAX approximately 5 to 6 milliseconds to receive the ACK and start 
transmission of the next record.  For this reason, it is desirable to have the 
record size as large as possible.  There is a buffer in the AMS that holds 
the record sent by the VAX and I could not determine its size.  This means
I don't know how large a record it takes to blow up the AMS.  For now, it seems
to work fine with a record size of 250 and we cannot do much better with a
larger record size, so let's use that size until someone determines the real 
buffer size.
	TYPE TEKHEX.HEX		56.0 seconds with parity set at 9600 Baud
	TYPE TEKHEX.HEX		50.5 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=32	29.3 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=64	22.5 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=96	20.8 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=128	19.9 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=200	19.2 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=250	18.7 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=300	19.1 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=400	18.8 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=500	18.9 seconds with no parity at 9600 Baud
	DNL  TEKHEX.HEX/rec=infinte	17.1 seconds in theory at 9600 Baud

A new version of DOWND has been released. This one, in conjunction with
Logg's new AMS Eproms, will allow for downloading symbols. It works
just the same as the old DOWND except it has two new options:

	/NOSYMBOL	- if you don't want symbols downloaded
	/SYMBOL_ONLY	- if you want only symbols (no data)

It will normally download symbols if there are any in the .HEX or .VLDA
file(s).

ds