# HG changeset patch # User Paul Boddie # Date 1598128938 -7200 # Node ID 97a40f11dd1c9d76075f42a450a08c668ca04859 # Parent 940fdf55c25170d5858e741815a1114eeeedacb6 Added more component pricing details and discussion. diff -r 940fdf55c251 -r 97a40f11dd1c Electron.txt --- a/Electron.txt Sat Aug 01 01:33:30 2020 +0200 +++ b/Electron.txt Sat Aug 22 22:42:18 2020 +0200 @@ -131,7 +131,7 @@ October 1982 £4.20 (Happy Memories, Opus Supplies) February 1983 £3.55 (Happy Memories) -The 150ns is reported as costing £4.00 in a Technomatic advertisement in +The 150ns part is reported as costing £4.00 in a Technomatic advertisement in February 1983. It may be the case that UK retail advertising does not illustrate the sudden decline from the initial pricing of the 4164 to its eventual pricing with sufficient availability. However, a general indication @@ -140,10 +140,92 @@ rated at 200ns and described as a 64Kbit part, at a unit price of £11.00 in volume. +US pricing in sources such as Byte magazine may offer a more complete picture. +64Kbit dynamic RAM parts are advertised as early as June 1981, with 4164 parts +having 250ns row access times being offered as low as $45.00 per chip. The +pricing at one vendor - Jameco Electronics - can be tracked over several +years: + + 150ns 200ns 250ns +June 1981 $49.95 +January 1982 $19.95 +April 1982 $14.95 +January 1983 $7.49 $6.87 (multiples of 8) +April 1983 $7.49 $6.87 (multiples of 8) +October 1983 $7.49 $6.87 (multiples of 8) +May 1985 $3.94 $3.74 (multiples of 8) +October 1986 $1.25 $1.15 + Other contemporary microcomputers offered 64K RAM using 4164 parts, such as the Sony SMC-70 and, more pertinently, the Atari 800XL. The latter of these appears to have employed 150ns-rated parts - eight as indicated above - and -may have had a broadly similar production cost to the Electron. +may have had a broadly similar production cost to the Electron. Meanwhile, the +AT&T Unix PC (featured in Byte, May 1985) employed 64 4164 parts to provide +512K RAM. + +Support Components and Economic Considerations +---------------------------------------------- + +Aside from the choice of RAM products, the ULA was designed to eliminate +various other discrete components from the design, notably the display +controller (6845 CRTC) and the sound generator (SN76489) used by the BBC +Micro. Pricing information for these parts can also be found in computing +magazines. For example, from JDR Microdevices advertisements in Byte magazine: + + 6845 SN78469 4164 (150ns) +April 1982 $16.95 +April 1983 $14.95 $8.95 $6.95 +May 1985 $12.95 $8.95 $2.44 + +Thus, the integration performed by the ULA could have saved approximately $24 +by eliminating these chips and providing supposedly sufficient capabilities +itself. + +Considering the need for only 4 RAM chips to provide 32K RAM, so as to be as +capable as the BBC Micro (but apparently not more capable), and considering a +price of $6.95 for 150ns 4164 RAM from the same vendor, an additional $28 +could have been saved, yielding savings of up to $52. However, it is likely +that greater savings would have been expected, and it remains debatable as to +whether the additional complexity, costs and delays would have been worth such +ultimately modest savings. + +Indeed, it is worth investigating anticipated costs and savings given the +pricing of dynamic RAM at different times: + + 4 * 4164 (32K) 8 * 4164 (64K) +1981 $200 $400 +1982/01 $80 $160 +1982/04 $60 $120 +1983 $28 $56 +1985 $10 $20 + +Clearly, the Electron would have been an expensive machine in 1981 had it been +designed around 64Kbit dynamic RAM. With 1982 pricing, the RAM chips would +have accounted for a considerable proportion of the machine's cost even with +the use of only 4 memory chips, and it is probable that the design strategy +may have been informed by the pricing at this time. With 1983 pricing, even +early in the year, it becomes apparent that the cost savings of using 4 memory +chips are becoming marginal. + +Indeed, combining the cost of 8 memory chips in 1983 with those of the +eliminated chips yields costs as much as or less than the 4-chip product at +the start of 1982: + + Components Total +8 * 4164 (64K) $56 +SN76489 + $9 = $65 +6845 + $15 = $80 + +Naturally, the board layout would be more complicated with more chips on the +board and this would increase costs somewhat. Given the role of the ULA in +generating a video signal and the generally robust pricing of the 6845, there +would certainly be a real motivation to eliminate the part from the design. + +In other words, anticipating lower memory pricing, designing for 8-bit access +to 8 RAM chips, and incorporating eliminated support chips would have resulted +in the same product cost outcome as that originally envisaged, but with the +ultimate benefit of a more capable computer with twice the RAM and improved +sound (and perhaps display) capabilities. Improving Display Capabilities ------------------------------