Can data files be synchronized between various OS devices?

Question

I am running 2 MacBook Pros, and 3 (4th ordered) Mac mini's with OS Yosemite 10.10. I am the only user of these devices (reason = personal convenience).
My problem is that because the Mac's are not synchronized (adding, deleting or modifying a file on one device does not do the same on my other devices) I now have up different versions of the same files on various devices.
Back with DOS and Windows I had a program Smart Copy (or Laplink) that enabled me to connect my PC's together and replace older (or nonexistent) files with new versions.
It has frustrated me since my first Mac that I have been unable to do this with my Mac's.
I even bought a Mac mini Server hoping to use this somehow to synchronize the Mac's but that did not help.
Is there a way (program, hardware etc.) that would enable me to assure that I have the same files on all my Mac's?
All my Mac's are upgraded to Yosemite 10.10 and I do have a Thunderbolt cable.
Thanks

Answer 1

Well, im trying to write an emulator for a specific instruction set and im trying to implement the memory part
of the emulator, the problem is that instructions are represented in binary along with their data types, so for now
im trying to write a write operation for the memory which write 32 bits to a memory address (address being the index of the array) and a read operation to read 32 bits from a memory address.
in the write stage i simply have:
public void write(int address, Integer data)
         if(address < this.base || address > this.base + MemoryMap.size() - 1)
              System.err.println("Invalid Write Access in Memory");
         else
              if(MemoryMap.size() > this.size)
                   System.err.println("Out of Memory");
              else
                  MemoryMap.add( (address - this.base) , data);
    }but im having problems with the idea of having an integer as an input, not sure how to handle this. Would array of bytes do? Also reading or outputing the information would be a problem unless i convert the integer to binary. MemoryMap is a ArrayList.