The definition information for symptom substitution is provided by Stedman's. You can search our medical dictionary here. Stedman's, part of Lippincott Williams & Wilkins, provides a comprehensive line of health-science publications for healthcare professionals and medical students.
Gigabyte: A Gigabyte is approximately 1,000 Megabytes. A Gigabyte is still a very common term used these days when referring to disk space or drive storage. 1 Gigabyte of data is almost twice the amount of data that a CD-ROM can hold. But it's about one thousand times the capacity of a 3-1/2 floppy disk. 1 Gigabyte could hold the contents of about 10 yards of books on a shelf. 100 Gigabytes could hold the entire library floor of academic journals.
Megabytes (MB) 109 bytes (base 10) Gigabyte (GB) is one of the most commonly used units of digital information which is equal to 1,000,000,000 bytes. However, in computer operating science, the value of 1 GB is considered to be equal to 230 or 10243 bytes which is equal to 1,073,741,824 bytes.