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From April 1st, 2021 @Electronic Design
What you’ll learn
- Why WOM?
- How Signetics started the WOM trend.
- The technology behind an M.2 WOM SSD.
Signetics was a silicon vendor that had a sense of humor before it got gobbled up by the competition. Its 25000 Series 9C46XN random-access write-only memory (WOM) employed enhancement and depletion-mode P-channel, N-channel and Neu-channel MOS devices (Fig. 1). It has a pass-through clock generator and one of the first Chip Destruct inputs. The patented technology, “You have a dirty mind. S.E.X. is a Signetics Extra Secret process. One Shovel Full to One Shovel Full, patented by Yagura, Kashkooli, Converse and AL, Circa 1921,” exceeded all expectations.
The technology was put on the shelf as the memory market moved to bipolor and CMOS to NAND, MRAM, and phase-change memory. The current crop of high-performance storage is built around PCI Express (PCIe) and NVM Express (NVMe). These high-speed serial interfaces provide significantly better throughput, with PCIe Gen 5 delivering 32 G transfers/s. The 25000 series was fast, but none of the processors of the day can keep up with the latest x86, RISC-V, and Cortex cores.
Impossible Technology’s 300-TB, 3.1415 Series NVMe WOM SSD (Fig. 2) fits in a standard M.2 socket. It’s the only M.2 device certified to meeting Gen 6.5 speeds of 95.69 Gtransfers/s. Unlike NAND-flash devices, this WOM has no write limitations, putting it on par with MRAM. The 3.1415 Series requires only 2.71828 nW of power.
The drive’s initialization sequence is 1 0(13) 666 0(13) 1. It has a cycle time of only 2^{aleph_0} ps. This allows the SSD to provide a data sink that can handle data streams from even the fastest processors currently on the market.
Impossible Technology has noted that getting the controller right was the hardest task. The actual memory storage was easy in comparison. The encryption engine is compact but capable of handling AES 1033/2053-bit keys and eucalyptus curve keys. The SSD retains Signetics’ Chip Destruct functionality, which is superior to secure erase normally found on encrypted SSDs. The 3.1415 Series also is totally immune to side-channel cyberattacks like those that use differential power analysis (DPA).
Read more at April 1st, 2021 @Electronic Design
