This line of output shows the current memory utilization for the system. The exact format for this list will vary from system to system. In general, the line will display amount of physical and virtual memory in use. Virtual memory is usually shown as swap space. Some systems will display two numbers separated by a slash (as in 4096K/1024K). The first number is the amount used "recently", otherwise known as active amount. The second number indicates total amount used.
Some systems will also display free amounts of physical memory or swap space.
Memory amounts may be displayed with a single letter suffix: K, M, or G. These indicate that the quantity displayed is in kilobytes, megabytes, or gigabytes, respectively. In each case, the measurements reflect base 2 (and not base 10). A kilobyte is 1024 bytes. Therefore, one million bytes (1,000,000) will be expressed as 977K and not as 1000K.