to find the memory from address lines. you just have to make address liness power of 2, as shown below for 12 address lines 212 bits. 212 = 22 * 210 = 4 Kb
that means we can address 4 Kb from 12 address lines.........
The number of address lines needed to access N-KB is given by log2N Then the number of address lines needed to access 256KB of main memory will be log2256000=18 address lines.
In a 256K x 16 memory system, the memory has 256K (256 * 1024 = 262,144) addressable locations and each location holds 16 bits of data. To calculate the number of address lines needed, we find the base-2 logarithm of 256K, which is 18 (since 2^18 = 262,144). For the data lines, since each location holds 16 bits, 16 data lines are required. Thus, the system requires 18 address lines and 16 data lines.
You need 20 bits of address bus to address 1 Mb of memory.
18
Memory Lane - 1947 - 1948-02-18 was released on: USA: 18 February 1948
Memory Lane - 1947 - 1948-03-18 was released on: USA: 18 March 1948
Memory Lane - 1947 - 1948-05-18 was released on: USA: 18 May 1948
Memory Lane - 1947 - 1948-06-18 was released on: USA: 18 June 1948
Memory Lane - 1947 - 1948-08-18 was released on: USA: 18 August 1948
Memory Lane - 1947 - 1948-10-18 was released on: USA: 18 October 1948
Memory Lane - 1947 - 1948-09-18 was released on: USA: 18 September 1948
Memory Lane - 1947 - 1948-11-18 was released on: USA: 18 November 1948