Tang, Jian jtang at
Mon Jun 23 01:29:34 PDT 1997

* From the SCSI Reflector (scsi at, posted by:
* "Tang, Jian" <jtang at>
Dear Sir/Madam,

I am an Engineer of Institute of Electronics, 
Chinese Academy of Sciences (Beijing, China).

I am very happy to have this opportunity to send e-mail to you,
and pleased to know you are one expert in SCSI-2/3 
Protocol Standards from SCSI-3 Working Set, Gloabal 
Engineering Documents (1995). 
Now, I have some questions to ask you, would you please
offer me some advice and helps ?
Thank you a lot in advance.

Problems are as follows:

We are designing and Debuging a High-rate data recording system,
with one 80c186 CPU & one NCR 53C720-SE(single-ended) SCSI-2 
Protocol Controler, and we use SCSI-2 HARD DISK for 
recording the data of about 10Mbytes/sec. 

The Problem we meet is that we Can NOT add the Synchronouse 
Data Transfer Protocal to the system, thus we can NOT nearly 
double the transmision speed. 
We can NOT add the feature of Synchronouse Data 
Transfer, though we have succeeded in finishing the 
Wide and Asynchronous Data Transfer for SCSI-2 Hard DISK.
So, the Highest date rate of our system is about 2Mbytes/sec,
and is far to reach the 10Mbytes/Sec of SCSI-2 Standards.

We use 80c186 ASM Language, NCR 53c720 NASM Assemble, 
and SCSI SCRIPTS Languages. 
Our main References are SYM52C720/SE/53C770 SCSI I/O 
Processor - Programming Guide 1.0 and DATA Manual, 
SCSI-2 and SCSI-3 Standards and Data Manual, etc. 

Would you please help me add the Synchronous Data Transfer 
in SCSI-2 Hard Disk? 
Your any advice on it is highly appreciated !
I am looking forward to hearing from you.

My contact e-mail is:    jtang at  

Many Thanks,


Tang, Jian
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