2026-07-24 — furbelow

Morning, friend. Friday. The last real working day of the week, if you're the sort of person who counts Monday as a rehearsal.

(Furbelow — noun, English by way of the French falbala, first attested in London milliners' bills around 1701. It began life as a specific term for the pleated flounce sewn to the hem of a petticoat and spread within a decade, in the plural, to mean any showy trim added to any object. Samuel Johnson listed it in the 1755 Dictionary as "fur, or other ornament sewed on the lower part of a garment" and pulled his illustrative quotation from a Spectator essay by Addison complaining that his mother-in-law's skirt carried more furbelow at the hem than she had lace in her hair. The word did most of its useful work in the eighteenth century and coasted into ours mostly as a term of aesthetic disapproval — the sort of thing you accuse an over-designed slide deck of.)

Joke

The postmortem is scheduled for a time that does not conflict with the next outage.

Something genuinely interesting (and mostly unknown)

Joseph-Armand Bombardier was born in Valcourt, Quebec, on 16 April 1907, and was a mechanically preoccupied child in the way that is expensive to a father. At fifteen, in the winter of 1922, he took apart the family's Model T Ford engine, mounted it on a set of ash-wood runners with a hand-carved four-blade wooden propeller for thrust, and drove it across the frozen field behind his father's general store. His father, in the version told by Bombardier's widow, watched the machine run for two full circuits of the field, made him take it apart, and told him to finish his engineering degree first. He did not finish the degree. He apprenticed with a mechanic in Montréal from 1924 to 1926 and returned home to open Le Garage Bombardier in Valcourt in 1926, aged nineteen.

Through the late 1920s and the 1930s, out of that garage, he built and iterated on tracked snow vehicles more or less continuously. The Eastern Townships of Quebec take between three and four metres of snow in a normal winter, and until the middle of the twentieth century the region did not plough rural roads — from November through April, a farmer with a sick child, or a woman in labour, or a burst appendix, reached the doctor by horse-drawn sleigh, on foot, or not at all. Bombardier had running prototypes by 1928, tracked designs with sprocket-and-cog drive by 1932, and a working rubber-and-steel endless-track system patented by 1935. What he did not have, in the winter of 1933–34, was a machine he was willing to sell.

In January 1934 his second son, Yvon, aged two, developed acute appendicitis. Bombardier and his wife loaded the boy into their car and set out for the hospital at Sherbrooke, some 50 kilometres away. The roads were snowed in. The car got as far as Sainte-Anne-de-la-Rochelle, about halfway, and then it did not go any further. The next-nearest neighbour with horses could not be reached in time. The boy died of peritonitis in the days that followed.

Bombardier is documented as having said very little about it. His widow, in interviews late in her life, described the several weeks after the funeral as a period during which her husband entered the garage in the early morning and did not emerge until late at night. Whatever else happened in that garage in the first months of 1934, the outcome — filed with the Canadian Patent Office on 29 June 1937 and issued as Canadian patent 385,269 — was the B7: a seven-passenger enclosed snowmobile riding on a pair of the rubber-and-steel tracks he had been iterating on for a decade, powered by a Ford flathead V-8, steered by skis in front, fitted with a heated wooden cabin, automotive doors, and glass side windows. The B7 could carry seven adults and a driver over open snow at roughly 50 km/h. It could reach any farm in the Eastern Townships in any weather. It went on sale in the winter of 1937.

The first B7s went to rural doctors, priests, veterinarians, and school-bus operators. L'Auto-Neige Bombardier Limitée was incorporated in 1942. By the end of the Second World War the product line included the B7, the twelve-passenger B12, ambulance and postal-service variants, and a tracked military cargo hauler built to Canadian Army specification. The Ski-Doo — the single-driver, straddle-seated recreational snowmobile that most people mean when they say "Bombardier snowmobile" — did not appear until 1959, and got its name by printer's error: Bombardier had intended to call it the Ski-Dog, and the manufacturer's plate came back from the print shop reading Ski-Doo. The Ski-Doo sold about 225 units in its first year and something like 8,200 by 1963. By the mid-1960s the plant at Valcourt was building more recreational snowmobiles than commercial ones, and Bombardier's original market — rural doctors who couldn't otherwise reach a farm — was closing itself down as Quebec started ploughing its concession roads.

Bombardier Inc., the modern parent, went on to acquire Canadair in 1986, Learjet in 1990, de Havilland Canada in 1992, and the several European rolling-stock makers that eventually became Bombardier Transportation. All of it descends, in a legally unbroken line, from Le Garage Bombardier in Valcourt, and from a machine Joseph-Armand Bombardier began building in earnest in the first weeks after his son's funeral.

I want to flag that a few of the specifics above — the boy's exact age at death, the exact day in January, the odometer distance the car made it before stopping — vary between sources, and I've picked the most-cited version each time. The general shape of the story is not in dispute.

Primary sources:

• Roger Lacasse, Joseph-Armand Bombardier — le rêve d'un inventeur, Libre Expression, Montréal, 1988. The standard French-language biography, written from the family's private papers with the cooperation of Bombardier's widow.
• Larry MacDonald, The Bombardier Story: From Snowmobiles to Global Transportation Powerhouse, John Wiley & Sons, 2013. The English corporate history; less on the founder's life and more on the postwar expansion.
• Musée J. Armand Bombardier, Valcourt, Québec. The former garage and the adjacent Bombardier house are a public museum run by the family foundation. The original B7 prototype is on display, along with a reconstruction of the 1922 propeller machine built from photographs.
• Canadian Patent 385,269, filed 29 June 1937, issued in the name Joseph-Armand Bombardier. The B7 mechanical patent.

The B7 is in Valcourt. If friend is ever in the Eastern Townships in the summer, the museum is worth an afternoon.

A dev fact for the back pocket

Every Ethernet frame on Earth carries a two-byte field at offset 12 that is either a length or a type, and the receiver decides which by treating any value ≤ 1500 as a length and any value ≥ 1536 as a type. The 35-value gap between them is reserved and will never be assigned.

The reason is a three-year war between two committees that both won.

The DIX consortium — Digital Equipment Corporation, Intel, and Xerox — published Ethernet Version 1.0 in September 1980 and Ethernet Version 2.0 in November 1982. The frame format was clean: destination address (6 bytes), source address (6 bytes), then a two-byte EtherType field naming the upper-layer protocol (0x0800 for IPv4, 0x0806 for ARP, 0x86DD for IPv6, and so on), then the payload, then a four-byte CRC. Any station receiving a frame could tell in constant time which protocol stack to hand the payload to.

The IEEE 802.3 working group, tasked with standardising Ethernet under the LAN/MAN umbrella, produced its first draft in 1983 and its first published standard as IEEE Std 802.3-1985. The 802.3 frame is identical to DIX at every offset except one: instead of a type field at offset 12, 802.3 defined the two bytes as the length of the payload in octets. Upper-layer demultiplexing was pushed into the payload itself via the IEEE 802.2 LLC header and, later, the SNAP extension — which together take eight bytes to say what DIX Ethernet says in two. This is why every 802.3-only stack in the wild is, in practice, running Ethernet II with a SNAP header duct-taped on the front and a small performance penalty attached.

The two frame formats had to coexist on the same wire because the world had already deployed millions of DIX Ethernet cards. The disambiguation rule, codified in the later revisions of 802.3 and universally implemented in silicon, exploits the fact that the maximum payload of an 802.3 frame is 1500 bytes and every EtherType value ever assigned by Xerox and later by the IEEE Registration Authority has been ≥ 0x0600 (1536 decimal). Any receiver seeing a value ≤ 0x05DC at offset 12 reads the field as a length and treats the frame as 802.3. Any receiver seeing a value ≥ 0x0600 reads the field as an EtherType and treats the frame as Ethernet II. The window between them — the 35 values from 1501 to 1535 inclusive — is permanently reserved, because assigning anything into that gap would collide with a decision the DIX committee made in 1980.

The ethertype column in tcpdump, the ETH_P_* constants in <linux/if_ether.h>, the frame parser in every switch ASIC currently manufactured, and the outer-header disambiguation in every VLAN, MPLS, and PPPoE stack you have ever touched all rely on this rule. The reason the default MTU on any wired network you touch is 1500 bytes is that in 1980 the DIX committee needed the 802.3 length field, if it were ever to exist, to fit comfortably under the smallest EtherType they had assigned. It has never moved, and cannot, without breaking every piece of Ethernet equipment ever built.

Primary sources:

• Digital / Intel / Xerox, The Ethernet — A Local Area Network — Data Link Layer and Physical Layer Specifications, Version 1.0, 30 September 1980. Widely known as the Blue Book. Scans circulate in the usual archival corners. The Version 2.0 revision followed in November 1982 and is the one implementations actually target.
• IEEE Std 802.3-1985, Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications. The first published 802.3, and the frame format that fought DIX to a truce.
• RFC 1042 (February 1988), A Standard for the Transmission of IP Datagrams over IEEE 802 Networks, by J. Postel and J. Reynolds. The IETF's contribution to the peace treaty: how to run IP over 802.3 using the LLC/SNAP encapsulation. Eight pages of Postel writing in the register of a diplomat who has been in the room for a very long time.
• IEEE Std 802.3-2022, clause 3.2.6 (Length/Type field). The current canonical statement of the rule, still in force and still using the words "if the value of this field is less than or equal to 1500 decimal, then the Length/Type field indicates the number of MAC Client data octets contained in the subsequent MAC Client Data field."

The frame format on friend's network this morning is a compromise between two standards bodies that spent three years disagreeing, resolved by a numeric threshold picked so neither side would ever have to concede. Every packet the machine sends today respects a boundary set in a Xerox conference room in 1980.

Today's goal

Write down, from memory, three phone numbers of people friend knows.

Not from the phone. Not from the contacts app. On paper, in ink, from memory alone. Do not open the phone until all three are down.

Almost nobody under thirty-five has three phone numbers memorised anymore. Most people have zero. This is a survival skill for the day the phone dies at the wrong moment — abroad, in an ER waiting room, after being pickpocketed on a train — and it costs nothing to keep and everything to lose. Once written, look them up and check. Where wrong, correct them and rewrite from memory tomorrow. Repeat until three of them stick.

Two hours a week, for a couple of weeks, buys back a piece of your grandmother's cognition.

Today's toy in the corner is furbelow — draw a line, any line, with the mouse or a fingertip, and the stroke sprouts small ornaments as it goes: leaves, curls, dots, tiny berries. Every stroke becomes trim. Every finished picture is fussier than the picture you meant to draw.

Go make something a little fancier than it needs to be, friend.

— C