We have no control over our customers' upgrade and capacity expansion plans, and we cannot be sure they will select, or continue to select, our equipment when they upgrade or expand their capacity. The sales cycle for our equipment systems can be a year or longer, involving individuals from many different areas of Intevac and numerous product presentations and demonstrations for our prospective customers. Our sales process also commonly includes production of samples and customization of our products. We do not typically enter into long-term contracts with our customers, and until an order is actually submitted by a customer there is no binding commitment to purchase our systems. In some cases, orders are also subject to customer acceptance or other criteria even in the case of a binding agreement.
As of December 30, 2023, our total backlog was $42.4 million, which was primarily attributable to two customers. Our backlog includes orders under contracts that can extend for several years. Our backlog can be significantly affected by the timing of large orders. We may not realize all of the revenue included in our total backlog in the future. For example, in fiscal 2023, we removed $66.0 million from backlog upon receiving notices from a customer of the cancellation of orders for ten 200 Lean HDD systems due to the customer postponing previously planned media capacity additions. There can also be no assurance that our backlog will result in revenue in any particular period because the actual receipt, timing and amount of revenue under contracts included in backlog are subject to various contingencies, many of which are beyond our control. If our customers terminate, reduce or defer orders, we may be protected from certain costs and losses, but our sales will nevertheless be adversely affected, and we may not generate the revenue we expect.
Sales of new manufacturing systems are also dependent on obsolescence and replacement of the installed base of our customers' existing equipment with newer, more capable equipment. If upgrades are developed that extend the useful life of the installed base of systems, then we tend to sell more upgrade products and fewer new systems, which can significantly reduce total revenue.
Our 200 Lean HDD customers also experience competition from companies that produce alternative storage technologies like flash memory, which offer smaller size, lower power consumption and more rugged designs. These storage technologies are being used increasingly in enterprise applications and smaller form factors such as tablets, smart-phones, ultra-books, and notebook PCs instead of hard disk drives. Tablet computing devices and smart-phones have never contained, nor are they likely in the future to contain, a disk drive. Products using alternative technologies, such as flash memory, optical storage and other storage technologies are becoming increasingly common and could become a significant source of competition to particular applications of the products of our 200 Lean HDD customers, which could adversely affect our results of operations. If alternative technologies, such as flash memory, replace hard disk drives as a significant method of digital storage, then demand for our hard disk manufacturing products would decrease.