problem in interfacing external RAM

I am able to access only the internal ON-CHIP RAM.

And how do you know that? I.e. what actually happens (cloud of black smoke, oscilloscope displaying something...), if you try to use MOVX memory at a position where there's no internal memory?

Does it work in the simulator?

I am able to access only the internal ON-CHIP RAM.

And how do you know that? I.e. what actually happens (cloud of black smoke, oscilloscope displaying something...), if you try to use MOVX memory at a position where there's no internal memory?

Does it work in the simulator?

I am using HMNR1288D RAM.It has only one chip enable pin.

Variable intialisation:

xdata unsigned char cCommonBuf1[500],cCommonBuf2[30];
char xdata text[1256] _at_ 0x0800; /* array at xdata 0xE000 */

	memset(text,'a',500);
	text[490] = 0;
	if(!strncmp(text,"aaa",3))
		SendByte('s');
	else
		SendByte('f');

	memset(text,'a',500);
	text[490] = 0;
	if(!strncmp(text,"aba",3))
		SendByte('s');
	else
		SendByte('f');

But in Real time interfacing with RAM,it is always sending 'f' to my hyperterm.

whta is the problem?

Almost certainly your hardware. Dig out your oscilloscope, and check that your chip enable is actually getting enabled, and that the address/data lines move as expected.