China DOS Union

Reference materials say that CCDOS does not support direct screen writing, so I did the corresponding experiment with CCDOS97.
The method is as follows:

We know that the E command in DEBUG can directly modify memory, so I used the E command to write some things to B800:0000, specifically as follows:
C:\>DEBUG
-E B800:0000
B800:0000 XX.40
-
XX is the hexadecimal representation of the ASCII code of the character at the upper-left corner of the screen, and it may differ
At this point we can see the result: an @ character appears in the upper-left corner of the screen!
This shows that CCDOS does support direct screen writing, at least the version I used does
Below are pictures of the experiment

Notice the character in the upper-left corner

Later I found the corresponding direct screen writing setting in the settings, as shown below:

Notice the setting below

Maybe this is an improvement in later versions of CCDOS

The original CCDOS, that is, CCDOS 2 through 4 produced by the Ministry of Electronics Industry, did not support direct screen writing, and later it declined.
CCDOS97 was written by Chen Jiangning, the core of the Tianhui Chinese character support system, combining the strengths of UCDOS and Tianhui, so of course it supports direct screen writing.
CCDOS97 has no direct relationship with the earlier CCDOS.

Then why didn't CCDOS97 combine AW97's strengths and support GBK characters?

So that's why the books say CCDOS doesn't support direct screen writing, but this one can

Maybe it's because of the input method. Chen Jiangning was skilled in operating systems, and also had never made a GBK system, so he may not have known input methods that well. Chen Aiwen, on the other hand, was the inventor of the shape-based code, and Stone had long since had a large-character-set Chinese character support system that supported CJK internal encoding.
Besides, judging from the performance of AW96 and AW97, many people would think there was no need for a CJK Chinese character support system under DOS.